The effect of Losartan on insulin resistance and beta cell function in chronic hemodialysis patients.

Insulin resistance (IR) is prevalent in hemodialysis patients. IR and hyperinsulinemia have an important role in the development of atherosclerosis, which is the most common cause of morbidity and mortality in hemodialysis patients. Thus, antihypertensive drugs that lower IR, may have an additional beneficial effect in the treatment of cardiovascular diseases in these patients. In this preliminary study we examined the effect of Losartan (an angiotensin II receptor antagonist) treatment on IR and beta cell function in five hypertensive non-diabetic chronic hemodialysis patients. All other known causes of IR in end stage renal failure were excluded. After a washout period of two weeks, Losartan 50 mg, was administered for 6 weeks. Fasting blood glucose (FBG) and insulin levels were measured before and after the treatment IR and beta cell function were calculated using the "homeostasis model assessment"-HOMA. Systolic and diastolic blood pressure (BP) have not changed significantly throughout the study. FBG increased significantly from 76 mg/dL +/- 1 to 89 mg/dL +/- 4 (p < 0.01), however, insulin levels have not changed significantly. Calculated IR values did not show a difference, but calculated beta cell function decreased significantly after Losartan treatment from 291% +/- 50 to 146% +/- 10, (p < 0.016). These preliminary results suggest that in chronic hemodialysis hypertensive non-diabetic patients short treatment with Losartan has deleterious effect on glucose homeostasis mediated via a decrease in beta cell function.

Red eye syndrome: clinical and experimental experience in a new aspect of diffuse eosinophilic infiltration?

Twenty-two of 24 hemodialysis patients dialyzed simultaneously with a new batch of cellulose acetate dialyzers promptly developed a spectrum of symptoms and physical signs including red eyes, hearing loss, tinnitus, and bone pain, previously described as red eye syndrome. We subsequently injected 4 rabbits with an eluate from a dialyzer of the same or a control batch. Six hours following exposure, the animals developed, in addition to red eyes, diffuse eosinophilic infiltration of various organs as well as myopathic changes and moderate brain edema. On the basis of these data, we suggest that it cannot be concluded whether the underlying pathophysiological mechanisms were toxic, allergic or both and that the occurrence of relevant symptomatology in 2 or more simultaneously dialyzed patients is a strong argument against unnecessary diagnostic or therapeutic procedures. Finally, a second exposure in a given patient should be avoided.

Effect of grapefruit juice on the pharmacokinetics of losartan and its active metabolite E3174 in healthy volunteers.

Grapefruit juice (GJ), a cytochrome P450 (CYP) 3A4 inhibitor, may affect the pharmacokinetics of drugs metabolized through CYP 3A4. Losartan, an angiotensin II antagonist, is converted into its main active metabolite E3174 by CYP 3A4 and CYP 2C9. The effect of GJ on losartan pharmacokinetics was assessed in a randomized crossover trial. Losartan was given to 9 volunteers with and without GJ. Concentrations of losartan and its E3174 metabolite were determined in serum by a high-performance liquid chromatography method (HPLC). Significant differences were observed in some of the pharmacokinetic parameters of losartan and its metabolite E3174 after losartan administration with and without co-administered GJ. The lag time (time to drug appearance in serum) of losartan increased significantly with co-administered GJ. The mean residence time (MRT) and half-life (t(1/2)) of the E3174 metabolite were significantly longer and the area under the concentration--time curve (AUC) of the E3174 metabolite was significantly smaller after concomitant GJ administration. The ratio AUC(losartan)/AUC(E3174) was significantly increased after concurrent grapefruit juice intake. The increased lag time of losartan and the increased MRT and t1/2 and decreased AUC of E3174 were considered indicative of simultaneous CYP 3A4 inhibition and P-glycoprotein activation. The significantly increased AUC(losartan)/AUC(E3174) ratio, however, indicates reduced losartan conversion to E3174 by CYP 3A4 metabolism as a result of co-administered GJ.

Vitamin B(6) therapy does not improve hematocrit in hemodialysis patients supplemented with iron and erythropoietin.

BACKGROUND/AIM: Pyridoxine deficiency may be the cause of failure to respond appropriately to iron and erythropoietin (EPO) administration in hemodialysis patients. METHOD: We studied 36 patients on chronic hemodialysis amply supplemented with iron and EPO, who failed to raise hematocrit levels >33%. Patients were divided into three equal groups and evaluated for 6 months as follows: Group A -- no additional therapy; group B -- supplemented with oral pyridoxine 50 mg/day, and group C received 100 mg/day pyridoxine orally. RESULTS: In all our patients, erythrocyte pyridoxine levels were initially within reference range for a healthy population and did not vary significantly during the study period. Likewise, ferritin levels and iron saturation values remained normal and constant. Hemoglobin and/or hematocrit levels remained practically unchanged in all three groups. CONCLUSIONS: The results indicate that in hemodialysis patients with normal pyridoxine status who, despite appropriate supplementation of iron and EPO, fail to reach optimal hematocrit levels, additional pyridoxine treatment does not produce any hematocrit elevation.

Pharmacokinetics of intraperitoneal piperacillin/tazobactam in patients on peritoneal dialysis with and without pseudomonas peritonitis.

OBJECTIVE: The objective of this study was to assess the pharmacokinetics of intraperitoneal (IP) administration of the antibiotic combination piperacillin/tazobactam (PIP/TAZ) to patients on chronic ambulatory peritoneal dialysis (CAPD) with and without pseudomonas peritonitis. DESIGN: Open-labeled study. SETTING: The study was carried out in the CAPD unit of Assaf Harofeh Medical Center, Zerifin, Israel. PATIENTS AND METHODS: Six patients participated in the study, 4 had pseudomonas peritonitis, all were given an IP loading dose of 4 g/0.5 g PIP/TAZ. Twenty-four hours after the initial dose, a maintenance dose of 0.5 g/0.0625 g PIP/TAZ was administered with each dialysate exchange for a period of 1 week. The patients without peritonitis received only the loading dose. High performance liquid chromatography was used to determine the concentrations of PIPITAZ in plasma obtained at 0, 30, 60, 90, 120, 360, 480, 600, 720, and 1440 minutes after administration. Samples of the dialysate fluid for determination of PIP/TAZ concentration were collected at 6,10,14, 24, and 72, 120, and 168 hours. RESULTS: After the loading dose, the highest plasma PIP concentration (Cmax) was 51.6 t 21.25 Lig/mL and appeared at 1.5 = 0.45 hours (t,,a). During the maintenance period plasma PIP concentration was 5.2 t 4.75 Lg/mL. Tazobactam was detected in the plasma of 1 patient only. The concentration of TAZ in the dialysate fluid during the maintenance period was 2.3 t 0.5 ig/mL. CONCLUSIONS: Piperacillin administered IP at 4 g reached plasma concentrations comparable to intravenous administration and considered therapeutic (above the MIC90 for Pseudomonas aeruginosa) in CAPD patients with or without peritonitis. The maintenance dose, however, should be augmented. Tazobactam could not be detected in the plasma of most patients and the therapeutic implications of IP administration of TAZ cannot be directly correlated to intravenous administration.

Nephrectomy enhances interleukin 6 secretion by interleukin 1-stimulated mesangial cells in vitro.

BACKGROUND: Kidney mesangial cells are capable of producing and responding to interleukin 6 (IL-6) . In experimental glomerulonephritis mesangial cell proliferation correlates with increased IL-6 production. To investigate the involvement of IL-6 in post-nephrectomy compensatory hypertrophy, we studied the capacity of mesangial cells from single remaining kidneys to secrete IL-6 in culture. METHODS: Mesangial cells were obtained from uni-nephrectomized or sham-nephrectomized Charles River rats. Cell cultures were maintained for 8 days in DMEM/FI2HAM medium supplemented with IL-1 of interferon (IFN). IL6 production was measured using an IL-6-dependent B9 human hybridoma cell line. RESULTS: IL-6 production by mesangial cells from normal kidneys was significantly enhanced by IL-1, compared to unstimulated cells (p<0.01), and the increase was significantly greater in mesangial cells from a single remaining kidney (p<0.01). All cultures grown in control medium or with addition of IFN produced similar amounts of IL-6. CONCLUSION: Mesangial cells from single remaining kidneys in culture maintain an exaggerated capacity to produce IL-6 in response to IL-1. IL-6 was reported to enhance or inhibit mesangial cell proliferation in vitro. We suggest that the local over production of IL-6 by a single remaining kidney may play a role in regulating a sequence of physiological events in compensatory renal growth, initially stimulating mesangial cell proliferation and later blunting the process.

The effect of grapefruit juice on the pharmacokinetics of orally administered verapamil.

OBJECTIVE: To investigate the effect of grapefruit juice (GJ) on the pharmacokinetics of orally administered verapamil in hypertensive patients. METHODS: Ten hypertensive patients on chronic verapamil treatment participated in a two-day study. On day 1 200 ml of water was given 1 hour before, and together with the morning verapamil dose; on the day 2, water was replaced by GJ in the same order. Serial blood samples were collected and the concentrations of verapamil and its main dealkylated metabolite (D-617) were determined by high-performance liquid chromatography (HPLC). The area under the concentration versus time curve of verapamil (AUCv) and its metabolite D-617 (AUCM) were calculated before and after GJ ingestion. The peak serum concentration (Cmax) and the time until its appearance (tmax) were also determined. RESULTS: GJ did not affect Cmax, tmax, AUCv or AUVm. The AUCv/AUCm ratio (AUCR) was slightly, but significantly, increased after GJ (1.67 vs 1.92). CONCLUSIONS: A single administration of GJ with short-acting verapamil has no significant effect on the pharmacokinetics, of verapamil.

Effects of captopril and enalapril on zinc metabolism in hypertensive patients.

OBJECTIVE: To investigate the effect of chronic captopril and enalapril treatment on zinc metabolism in hypertensive patients by assessing zinc levels in serum, urine and monocytes. METHODS: Patients with newly diagnosed essential hypertension were randomly divided into two treatment groups: those treated with captopril only (n = 16) and those treated with enalapril only (n = 18). Ten healthy subjects served as controls. Prior to the start of treatment and again 6 months later, zinc was assessed in the serum, in urine collected over 24 hours, and in peripheral blood monocytes. RESULTS: Significant enhancement of 24-hour urinary zinc excretion (micrograms/24 hour) after 6 months of treatment was observed only in the captopril-treated group (p < 0.01). However, intramonocytic zinc levels decreased significantly in both of the treated groups over the same period (p < 0.01 and P < 0.04 in the captopril- and enalapril-treated groups, respectively). CONCLUSION: Treatment of hypertensive patients with captopril or enalapril may result in zinc deficiency.

Benign familial microcytic thrombocytosis with autosomal dominant transmission.

Familial thrombocytosis is an extremely rare disorder, so far reported in only a handful of families. In the majority of cases the characteristics were of essential thrombocythemia. Most patients presented with a platelet count above 800,000/mm3, were diagnosed as having a myeloproliferative disease, and some required chemotherapy. We describe a benign form of familial thrombocytosis with autosomal dominant inheritance in five healthy members of three generations of a family, all of whom had moderate thrombocytosis within the range 422,000-662,000/mm3, characterized by low mean platelet volume. A careful medical history and a 5-year follow up of the subjects did not reveal any untoward clinical development. This variant of familial thrombocytosis is therefore of a benign nature. Possible mechanisms linking thrombocytosis with platelet microcytosis in this family are discussed.

Conservative treatment for Brucella endocarditis.

Endocarditis is the most devastating complication of brucellosis. The accepted treatment for Brucella endocarditis (BE) is a combination of valve replacement and antibiotics. Conservative antibiotic treatment alone is not recommended by most authors, as it is considered ineffective, risking fatality. We describe a patient with BE, in whom antibiotic treatment alone resulted in complete recovery. On reviewing the literature, we found 12 additional such cases. We compared this group of 13 patients with data from 49 published cases treated with a combination of surgery and antibiotics, with a favorable outcome. Absence of congestive heart failure or a prosthetic valve, relatively mild extravalvular cardiac involvement, and a somewhat shorter disease history until initiation of treatment were characteristic of the group treated conservatively in comparison with patients who underwent surgery. In selected patients with BE, conservative antibiotic treatment may be a valid alternative to surgery.

[Quinidine-induced rheumatic toxicity].

2 women with quinidine-induced lupus are presented. This condition is rare; only about 30 cases have been reported in the English literature. Both our patients had arthritis of the wrist, antinuclear antibodies with homogenous pattern and elevated ESR. Anti-double stranded DNA antibodies were present in 1 patient, and a petechial rash in the other. Complete resolution of arthritis occurred within a few days after quinidine withdrawal, but antinuclear antibodies persisted for several months.

Chylothorax following median sternotomy.

Reports of chylothorax (CT) following median sternotomy are rare, amounting so far to 16 cases in the English literature, of which 6 were cases of postcoronary artery bypass grafting (CABG). This report deals with an additional case of a 70-year-old woman who developed left pleural chylous effusion following CABG. It is suggested that the incidence of this type of pleural effusion is considerably greater than the few cases hitherto reported. Moreover, as CT may produce serious pulmonary and/or pleural functional impairment, it is proposed that a diagnostic tap be performed more often in cases of post CABG pleural effusion and that preventive drainage be instituted when CT is diagnosed.

Effects of Various Modalities of Oral Furosemide Administration in Mild or Severe Congestive Heart Failure.

BACKGROUND: This study evaluated the optimal formulation (tablet vs solution) and frequency (once vs twice daily) of maintenance oral furosemide in compensated congestive heart failure (CHF). METHODS AND RESULTS: Eighteen patients with mild (group 1) and 18 with severe (group 2) CHF were studied. On 2 consecutive days each patient's individual fixed oral furosemide daily dosage was administered in tablet or solution in a crossover design. In an additional study, 14 patients with severe CHF received the daily dosage in tablet or solution form in two divided doses. Pharmacokinetic data were obtained in six randomly allocated patients of each group, during the once daily administration periods of either formulation. Twenty-four-hour urinary sodium and 12-hour volume were significantly greater in group 1 following furosemide solution versus tablets. In group 2, all parameters were comparable in response to single identical doses in tablets or solution, as well as to once versus twice daily administration of either formulation. These results coincided with a higher C(max) and a shorter t(max) following solution. CONCLUSIONS: A once-daily oral furosemide solution is more effective than the same dosage in tablet form in patients with mild, but not those with severe, CHF. In patients with severe CHF, the natriuretic and diuretic effects are similar whether oral furosemide in tablet or solution is administered in a once or twice daily schedule.

Effect of furosemide oral solution versus furosemide tablets on diuresis and electrolytes in patients with moderate congestive heart failure.

Oral furosemide solution was claimed to produce a greater diuretic response than furosemide tablets in patients with congestive heart failure. The aim of this study was to assess this observation and to further investigate the effects on the electrolyte balance. We compared the effects of oral furosemide in tablets versus oral furosemide solution on serum levels as well as on 4- and cumulative 24-hour urinary volume and sodium, potassium, calcium, magnesium and zinc excretions in 10 patients with moderate congestive heart failure due to ischemic heart disease. Oral furosemide (40-80 mg) was given at the usual once-daily dosage. No change in serum electrolyte levels has been found. All urinary parameters, except zinc, were significantly greater during the first 4 h following oral solution as compared with tablets (volume p < 0.001, sodium p < 0.001, potassium p < 0.05, calcium p < 0.003, magnesium p < 0.05). However, after 24 h, significant differences were found in urinary volume (p < 0.03) and sodium excretion (p < 0.004) only. We conclude that: (1) oral furosemide solution provides a more potent 24-hour diuretic and natriuretic effect than an identical dosage in tablet form, without entailing greater cumulative urinary losses of potassium, calcium, magnesium, and zinc; (2) following the first 4 h of furosemide solution, brisk diuresis, kaliuresis, and magnesiuria are produced, and (3) despite the urinary losses, serum electrolytes remained within normal limits at 4 and 24 h.

Pancreatic enzyme elevation in measles.

During an outbreak of measles in the period from May 1993 through February 1994, a 23-year-old woman with measles was admitted because of abdominal pain and vomiting. Moderately elevated levels of serum and urinary amylase were found. We investigated prospectively the next nine consecutive young adults hospitalized with severe measles. Pancreatic and other organ involvement was determined by serum and urinary amylase, serum lipase, and additional appropriate biochemical and hematological data. Four patients had elevated amylase levels in both serum and urine, whereas in one, serum amylase alone was increased. Serum lipase determined in eight patients was elevated in seven. In all patients elevated serum levels of aspartate aminotransferase and alanine aminotransferase or lactate dehydrogenase were found. In seven patients serum calcium concentrations were below the lower limit of normal. Four patients had mild to moderate thrombocytopenia. This is the first detailed report of pancreatic involvement in young adults with measles. This abnormal finding, its possible underlying mechanisms, and the clinical significance are discussed.