Q fever pneumonia: appearance on chest radiographs.

PURPOSE: To determine the radiographic features of Q fever pneumonia. MATERIALS AND METHODS: Chest radiographs in 85 patients admitted to the hospital during a 7-year period with Q fever pneumonia were retrospectively reviewed by two observers. RESULTS: The most commonly recorded abnormalities were segmental (n = 53 [62%]) and lobar (n = 15 [18%]) areas of opacity. Segmental pneumonia was observed as a unilateral single area of opacity in 38 (72%) patients. It was more frequently located in the upper lobes. The left upper lobe was involved in 31% of patients, the right upper lobe, in 23%; and the right lower lobe, in 27%. Lobar pneumonia was less frequently observed as a single lesion in eight (53%) of 15 patients; It was located in the left upper lobe in 31% and in the right middle lobe in 27% of patients. There was no correlation between the extent of pulmonary involvement and the course of the disease; the outcome was favorable in all patients. Complete resolution of the radiographic findings occurred in a mean of 39 days. CONCLUSION: The radiographic differentiation of Q fever pneumonia from the other community-acquired pneumonias is not possible. Clinical, serologic, and epidemiologic data provide the best basis for diagnosis.

Gram-negative bacteremia in non-neutropenic patients: a 3-year review.

The causative organisms, clinical manifestations, factors influencing prognosis, and other epidemiological characteristics of 81 episodes of bacteremia due to gram-negative organisms, in non-neutropenic patients, were studied retrospectively during a 3-year period (1992-1994) at the Department of Internal Medicine of the University Hospital of Heraklion, Crete, Greece. The gram-negative bacteremia incidence was 2% and the overall mortality 12%. All 81 patients had fever; Escherichia coli was the most frequent organism isolated (from 47 patients--58%) and was associated with shock (9/47), disseminated intravascular coagulation (DIC) (8/47), anuria (5/47), adult respiratory distress syndrome (ARDS) (3/47), and pneumonia (1/47). Other less frequent gram-negative microorganisms were Klebsiella spp. (ten patients; 12%), Pseudomonas spp. (7; 7%), Salmonella spp. (5; 6%), Enterobacter spp. (5; 6%), Proteus spp. (3; 3.4%), Stenotrophomonas spp. (3; 3.4%), and Acinetobacter spp. (1; 1.2%). ARDS. shock, DIC, anuria, presence of central venous catheter, urinary catheter, unknown origin of infection and inappropriate treatment were significantly associated with a higher death rate. Early initiation of appropriate therapy was the most important intervention that favorably affected the outcome of gram-negative bacteremias in this patient population.

Q fever in the Greek Island of Crete: epidemiologic, clinical, and therapeutic data from 98 cases.

A retrospective study was undertaken in Crete, Greece, to investigate the epidemiologic, clinical, and therapeutic aspects of Q fever. Over a period of 5 years (1989-1993), 1,298 patients were examined and 98 cases were identified. Individuals who were aged 20-29 years and 30-39 years appeared to have an increased risk of infection. Contact with animals was found to be a major risk factor for acquisition of Q fever. The predominant clinical manifestations of the infection were fever (91.7% of patients) and respiratory disease (88.5%), whereas hepatitis was the dominant feature in only a minority (7.1%) of patients. Chest radiographs frequently revealed pulmonary interstitial changes (36.4% of patients) and alveolar changes (34.4%). Abnormal echocardiographic findings were also observed. There was no difference in the duration of fever whether the patient received therapy with tetracycline or erythromycin, a finding that may be explained by the delay in initiating tetracycline therapy.

Prospective study of the impact of broad-spectrum antibiotics on the yeast flora of the human gut.

The effects of four antibiotics on the yeast flora of the human gut were evaluated. Forty adult cancer patients who received therapy with amoxicillin-clavulanate, ciprofloxacin, sulfamethoxazole-trimethoprim or ampicillin were studied prospectively. Quantitative stool cultures for yeasts were performed immediately before, at the end of and one week after the end of the antibiotic treatment. Amoxicillin-clavulanate caused a higher and more persistent increase in gastrointestinal colonization by yeasts compared to ciprofloxacin, sulfamethoxazole-trimethoprim or ampicillin. The present results are similar to those obtained in a mouse model of gastrointestinal colonization by Candida albicans when the same antibiotics were used.

Fluorometric study of serum in patients with chronic renal failure.

Sera from 84 uremic patients (53 on conservative treatment and 31 on hemodialysis) were studied spectrofluorometrically in comparison with 20 normal subjects and 11 jaundiced patients. Serum fluorescence in patients with chronic renal failure was significantly higher than in normals and patients with jaundice. Two types of serum fluorescence spectra (A and B) were predominant (93%) and all the patients who were free of any medication for more than two months exhibited the type A spectrum. The intensity of fluorescence was in parallel with the serum creatinine levels. Dialysis experiments of uremic serum in vitro showed that the substance(s) responsible for its fluorescence is dialyzable. Moreover hemodialysis caused a significant decrease in the intensity of serum fluorescence in dialyzed patients. Administration of pyridoxine intravenously caused quite different results in normal subjects and uremic patients. Namely normals presented a transient (for several minutes) increase in serum fluorescence whereas uremics showed a higher and more permanent increase which lasted for several days.

Renal effects of lithium administration in rats: alterations in water and electrolyte metabolism and the response to vasopressin and cyclic-adenosine monophosphate during prolonged administration.

Lithium (Li+) chloride, 2 to 3 mEq. per kilogram of body weight, was administered intraperitoneally to normal Wistar rats daily for 4 to 66 days. This resulted in a marked reduction in urine osmolality (Uosm.) and increase in the excretion of water, Na+, K+, uric acid, and phosphate. The excretion of uric acid and potassium was a direct function of UNaV. The magnitude of depression in urine osmolality was significantly related to the rate of excretion of lithium in the urine, suggesting that the change in water reabsorption is dependent on the presence of the ion in the luminal side of the tubule. During 2 per cent saline diuresis, Li+-treated rats achieved less fractional free water reabsorption (TcH2O/GFR times 100) at any level of fractional osmolar clearance (Cosm./GFR times 100) than normal rats. On the other hand, during 0.225 per cent saline diuresis, fractional free water clearance (CH2O/GFR times 100) was normal over a wide range of fractional urine flow (V/GFR times 100), indicating intact function of the ascending limb of the loop of Henle. The intravenous infusion of vasopressin (VP) or dibutyryl cyclic-adenosine monophosphate (dcAMP) to Li+-treated rats resulted in a modest rise in Uosm. and a reduction in V/GFR times 100 and CH2O/GFR times 100. Although the response to VP appeared earlier than that to dibutyryl cyclic-AMP, the magnitude of the changes in Uosm., V/GFR times 100, and CH2O/GFR times 100 was eventually the same with both substances. Comparison between normal and Li+-treated rats revealed that the response to both VP and dibutyryl cyclic-AMP was blunted, albeit to a greater extent in the former. Inhibition by Li+ of adenylate cyclase will only partially explain the present data. Impairment in the release of endogenous VP or a block distal to the formation of cyclic-AMP must have played a role. In view of a normal diluting capacity and the increase in the excretion of phosphate and uric acid, it is suggested that Li+, when administered chronically in the present doses, inhibits proximal tubular reabsorption.

Renal sodium-potassium-activated adenosine triphosphatase and sodium reabsorption.

The role of renal Na(+),K(+)-ATPase in sodium reabsorption was further examined in dogs in which digoxin, a specific inhibitor of the enzyme system, was infused into one renal artery in doses ranging from 0.4 to 0.9 mug/kg/min (low dose) and from 1.0 to 4.0 mug/kg/min (high dose). A significant natriuresis occurred with both dose ranges which was accompanied by inhibition of Na(+),K(+)-ATPase of cortex and medulla in the infused kidney. Despite over 90% enzyme inhibition in many experiments, at least 80% of the filtered sodium continued to be reabsorbed. The per cent change in enzyme activity correlated with the rate of digoxin administration and the total dose administered but not with changes in sodium excretion. Changes in medullary Na(+),K(+)-ATPase activity, however, bore a direct relationship to alterations in fractional solute free water reabsorption (T(c) (H2O)). Inhibition of cortical enzyme activity alone was not associated with natriuresis, suggesting that medullary enzyme activity must be depressed for increased sodium excretion to occur during digoxin infusion. In high-dose experiments, significant inhibition of cortical and medullary enzyme in the contralateral control kidney was also observed, but natriuresis did not occur. In these experiments the rate at which digoxin reached the control kidney rose progressively but never equaled the rates in the directly infused kidney with either dose. Nevertheless, it is clear that under certain circumstances enzyme inhibition of either cortex or medulla need not be accompanied by natriuresis. We conclude that the major role of renal Na(+),K(+)-ATPase is in sodium reabsorption in the medulla (ascending limb of Henle's loop) and that it has a relatively small role in proximal sodium reabsorption. The kidney can rely on other sodium reabsorptive mechanisms depending on the rate of enzyme inhibition, so that natriuresis may not occur at all if depression in activity occurs "slowly." The nature of these mechanisms is not clear.