Case/control study of the role of splenectomy in chronic lymphocytic leukemia.

PURPOSE: This retrospective analysis was performed to evaluate critically the morbidity and mortality of splenectomy in patients with chronic lymphocytic leukemia and to determine the probability of hematologic response. Further, using a case/control format based on multivariate analysis-derived predictors of survival, we evaluated the influence of splenectomy on survival. PATIENTS AND METHODS: Between 1971 and 1993, 55 patients with chronic lymphocytic leukemia underwent splenectomy. They were compared with 55 fludarabine-treated patients who had been matched for age, serum albumin level, sex, hemoglobin level, Rai stage, number of prior therapies, and time from diagnosis. RESULTS: In the perioperative period, blood-product usage was modest, and common morbidities were limited to minor infections in 18% of the patients and pneumonia/atelectasis in 25%. Perioperative mortality was 9%. Deaths were related to septic complications in all cases and associated with a preoperative performance status > or = 2 (P = .05). The only predictor identified for hemoglobin and neutrophil increments was spleen weight (P < .05). No factors predictive of platelet increment were identified. The early death rate (within 30 days) and overall survival of splenectomy and control patients were not significantly different (P > .2). Among Rai stage IV patients, those who were splenectomized displayed a strong trend for improved overall survival (P = .15 by log-rank test). The 2-year actuarial survival rate of Rai stage IV patients was 51% +/- 9% in the splenectomy group and 28% +/- 9% in the control group. CONCLUSION: Splenectomy can be performed with modest morbidity, mortality, and resource utilization in patients with advanced chronic lymphocytic leukemia and significant cytopenias. The procedure results in major hematologic benefits in most patients, with hemoglobin and neutrophil increments correlated with spleen weight. Overall, the survival of splenectomized patients is equivalent to control patients. Thrombocytopenic patients (< 100 x 10(9)/L) are most likely to obtain hematologic benefit, and potentially enjoy improved survival. These patients would be suitable for a randomized study to establish definitively the role of splenectomy in chronic lymphocytic leukemia.

Aspergillus terreus osteomyelitis.

Aspergillus terreus infection limited to the L1-2 disk space and first and second lumbar vertebrae developed in a patient not predisposed to invasive aspergillosis. The observation of morphologically distinct secondary spores (aleuriospores) on microscopic examination of open biopsy specimens permitted a preliminary identification of A terreus, which was confirmed by culture. The infection was eradicated with amphotericin B in a total dose of 3 gm. Aspergillus terreus is usually a saprophyte. The present case and four others collected from the literature establish this species as an invasive pathogen.

Randomized, double-blind comparative study of intravenous ciprofloxacin versus ceftazidime in the treatment of serious infections.

We compared intravenously administered ciprofloxacin with ceftazidime in a randomized, double-blind study. Patients received ciprofloxacin 200 mg intravenously every 12 hours or ceftazidime 2 g intravenously every eight hours, with placebo infusions to maintain blinding. Therapy with metronidazole was added for suspected or documented intra-abdominal infection. Thirty-two of the 57 ciprofloxacin-treated patients were evaluable for determination of efficacy and had 41 bacterial isolates from 34 sites. Thirty-six of the 56 ceftazidime patients were evaluable for determination of efficacy and had 41 bacterial isolates from 38 sites. Seven of 35 bacteremic patients had no identifiable primary focus. The most commonly isolated pathogens were Escherichia coli, Streptococcus pneumoniae, Staphylococcus aureus, and Klebsiella pneumoniae. Cure rates and bacteriologic eradication rates were comparable. Nine patients did not improve. Patients with treatment failures in the ciprofloxacin group included a quadriplegic patient with relapse of urinary tract infection with bacteremia (K. pneumoniae). Another patient with bacteremia (Pseudomonas aeruginosa), pneumonia (Proteus vulgaris), and urinary tract infection (P. vulgaris, Providencia sp.) died on the first treatment day. The third patient (S. aureus and Streptococcus pneumoniae pneumonia) had a new aspiration pneumonia develop on the third day; the pneumococcus also persisted. Undrained S. pneumoniae empyema caused the fourth ciprofloxacin treatment failure, and the fifth patient had a relapse of S. aureus pneumonia with bacteremia. One ceftazidime-treated patient died of pneumococcal pneumonia on the first day. Another had persistent Staphylococcus epidermidis and Listeria bacteremia despite 48 hours of treatment. Two other patients had pneumonia (S. aureus and P. aeruginosa, respectively) and completed full courses of ceftazidime therapy without improvement. Five patients had pneumococcal bacteremia; four patients were cured: one of two patients in the ciprofloxacin group and three of three patients in the ceftazidime group. Significant increases in the number of platelets (four patients with ciprofloxacin treatment, one patient with ceftazidime treatment) and declines in the number of platelets (one patient with ciprofloxacin treatment, one patient with ceftazidime treatment) were observed. Intravenously administered ciprofloxacin is comparable with ceftazidime and is a safe and effective antibiotic for the treatment of patients with serious infections, including bacteremia.

Comparative clinical studies of ototoxicity and nephrotoxicity of amikacin and gentamicin.

A comparative study of the oto- and nephrotoxicity of amikacin and gentamicin was carried out prospectively. Twenty-six gentamicin-treated patients and 27 amikacin-treated patients were monitored for changes in auditory and renal function during and after therapy. Thirteen of those treated with gentamicin and 20 of those treated with amikacin underwent vestibular caloric testing which could be evaluated for evidence of toxicity. In four (15.4%) of the gentamicin-treated patients, nephrotoxicity developed; no such toxicity was seen in the amikacin-treated patients. This difference may have been due to a fortuitously higher incidence of pretreatment renal impairment in the gentamicin-treated group. In two gentamicin-treated patients (7.7%), ototoxicity developed (one auditory, one vestibular), and in two amikacin-treated patients (7.4%), auditory toxicity developed. Statistical analysis of oto- and nephrotoxicity and their risk factors was not attempted because of the small numbers of patients who could be evaluated. Additional patients are being studied.

Clinical isolation and characterization of aminoglycoside-resistant small colony variants of Enterobacter aerogenes.

Small colony variants of Enterobacter aerogenes, as well as the parental large colony type, grew in blood drawn for cultures on three separate days from a patient who had received suboptimal gentamicin therapy. Minimum inhibitory concentrations of four aminoglycoside antibiotics were eight to more than 16 times higher for small colony variants than for the normal large colony type. Small colony variants had defective catalase activity, which may have interfered with oxidative metabolism and aminoglycoside uptake. Small colony variants reverted readily to the parental type in vitro in the absence of aminoglycosides. Clinically isolated small colony variants appeared similar to those selected in the presence of gentamicin in vitro, with respect to colony morphology, aminoglycoside resistance and catalase deficiency. The isolation of small colony variants during gentamicin therapy in vivo suggests that such variants may be a cause of treatment failure in patients receiving aminoglycosides.

Comparative study of ototoxicity and nephrotoxicity in patients randomly assigned to treatment with amikacin or gentamicin.

Fifty-four patients treated with gentamicin and 52 patients treated with amikacin were evaluated for nephrotoxicity and ototoxicity in a prospective, randomized, blinded comparative trail. According to our definition of nephrotoxicity (an increase in serum creatinine levels to at least 50 percent and 0.5 mg/dl above the baseline value), nephrotoxicity occurred in eight (15 percent) of the patients who were treated with gentamicin and none of the patients who were treated with amikacin (p = 0.006). Using several other definitions of nephrotoxicity, the differences in incidence between the treatment arms were not significant. Nephrotoxicity appeared to be associated with impaired baseline renal function, greater age, and the presence of bacteremia. Ototoxicity occurred in six (11 percent) of the 54 gentamicin-treated patients; auditory toxicity occurred in three patients, and toxic changes were observed in three of the 33 patients who could also be evaluated for vestibular toxicity. Similarly, ototoxicity was observed in seven (13 percent) of the 52 amikacin-treated patients; auditory toxicity occurred in four patients, and of the 34 patients who could also be evaluated for vestibular toxicity, three exhibited vestibular toxicity without auditory toxicity are one experienced vestibular effects in addition to those affecting the cochlea. We observed a modest association of ototoxicity with nephrotoxicity and with an elevated mean trough aminoglycoside serum level. The results of this study indicate that amikacin may be less nephrotoxic than gentamicin in humans; however, the broad applicability of this finding to other patient populations is uncertain.

Chloroalanyl antibiotic peptides: antagonism of their antimicrobial effects by L-alanine and L-alanyl peptides in gram-negative bacteria.

A large number of structurally diverse di- and tripeptides containing the alanine racemase inactivator beta-chloro-L-alanine (beta-Cl-LAla) have been synthesized, and their antibacterial properties in vitro have been evaluated. The dipeptides 1, 3-6, and 8-17 and the tripeptide 20 are all broad-spectrum antibacterial agents with considerable potency against both Gram-positive and Gram-negative species, but none of these peptides improves dramatically on the antibiotic efficacy of the previously described beta-Cl-LAla-beta-Cl-LAla, 9 (Cheung, K. S.; Wasserman, S. A.; Dudek, E.; Lerner, S. A.; Johnston, M. J. Med. Chem. 1983, 26, 1733). Gram-negative microorganisms, such as Escherichia coli, Hemophilus influenzae, Shigella flexneri, and Enterobacter species are consistently resistant to any haloalanyl peptide containing an alanyl residue, such as the dipeptide LAla-beta-Cl-LAla (2) and the tripeptides LMet-LAla-beta-Cl-LAla (7), LAla-LAla-beta-Cl-LAla (18), and LVal-LAla-beta-Cl-LAla (19). Correspondingly, these same organisms are protected from the bactericidal effects of 9 by supplementation of the growth medium with LAla or LAla-LAla. Escherichia coli JSR-O exposed to 9, but protected from lysis by sucrose stabilization, has only about 10% the normal level of intracellular alanine racemase activity. But when these cells are cultured in the presence of 9 with LAla supplementation, or in the presence of 2 with no supplementation, the alanine racemase levels are only about 20-30% below control values. These findings suggest that the resistance of Gram-negative species to chloroalanyl peptides containing alanyl units arises from the ability of LAla to protect the targeted racemase from inactivation by beta-Cl-LAla in vivo, an event which otherwise leads to cell death and lysis. Inactivation of alanine racemase in Gram-positive organisms appears not to be the cellular event that confers sensitivity of these species to a haloalanyl peptide.

Chloralanyl and propargylglycyl dipeptides. Suicide substrate containing antibacterials.

A set of dipeptides containing the amino acid residues beta-chloroalanine and propargylglycine, which are mechanism-based inactivators of purified microbial enzymes (alanine racemase and cystathionine gamma-synthase, respectively), have been synthesized, and their antibacterial properties in vitro have been evaluated. Dipeptides containing a single beta-chloro-L-alanyl residue (e.g., 3, 5, 9, and 10) or a single L-propargylglycyl residue (e.g., 12 and 15) are potent antibacterials. The in vitro antibiotic activity of beta-chloro-L-alanine and of L-propargylglycine is increased as much as 4000-fold by incorporation of these residues into a dipeptide. Compounds that contain only a single enzyme-inactivating amino acid together with a second L-alanyl residue (3, 5, 12, and 15) have a restricted range of activity: of the species tested, only Streptococcus agalactiae, Staphylococcus aureus, and Staphylococcus epidermidis are sensitive. However, peptides that contain two suicide-substrate residues [e.g., beta-Cl-LAla-beta-Cl-LAla (8) or LppGly-LppGly (18)] are broad-spectrum antibacterials; as many as 12 different species of the 16 surveyed are sensitive. Dipeptides that contain an amino-terminal L-methionyl (9) or an L-norvalyl (10) residue and a carboxy-terminal beta-chloro-L-alanyl unit are also effective against a large number of organisms; the spectra of activity are like those seen for 8 and 18. A "mixed" dipeptide [beta-Cl-LAla-LppGly, (21)] gives apparent synergism of antibiotic action of beta-chloro-L-alanine and of L-propargylglycine when these two residues are incorporated into a single structure. Peptides of the D,D configuration (4, 6, 13, 16, and 20) and ones of L,D stereochemistry (e.g., 7) are not antibacterials. Peptides containing one (11 and 14) and two (17) D,L-propargylglycyl residues are unresolved sets of diastereomers; the mixtures of compounds are between two- and fourfold less active than the correspondingly resolved L,L dipeptides (12, 15, and 18). These findings are consistent with a mechanism of action for these antibiotics involving stereoselective processing of the peptidyl unit in vivo.

High-level amikacin resistance in Pseudomonas aeruginosa associated with a 3'-phosphotransferase with high affinity for amikacin.

This work describes the characterization of the phosphotransferase enzymatic activity responsible for amikacin resistance in two clinical Pseudomona aeruginosa strains, isolated from a hospital that used amikacin as first-line aminoglycoside. Amikacin-resistant P. aeruginosa PA40 and PA43 (MIC: 128 mg/l) were shown to have APH activity with a substrate profile similar to that of APH(3')-VI. The enzyme from P. aeruginosa PA40 was purified to > 70% homogeneity. The Km of amikacin for this enzyme was 1.4 microM, the Vmax/Km ratio for amikacin was higher than for the other aminoglycosides tested and PCR and DNA sequencing ruled out the presence of aph(3')-IIps. Amikacin resistance in this strain was, therefore, associated with APH(3')-VI and the high affinity of this enzyme for amikacin could explain the high-level resistance that we observed.

Single daily dose therapy with aminoglycosides.

Although aminoglycosides are generally infused every 8 or 12 h, recent data suggest that administration of the total daily dose every 24 h may reduce the risk of oto- and nephrotoxicity and improve efficacy. Aminoglycosides kill bacteria in a dose-dependent manner (i.e. the higher the drug level, the more rapid and complete the bactericidal effect), and exert a post-antibiotic effect (delay in regrowth after the drug concentration falls below its minimum inhibitory concentration for the strain). Moreover, survivors after initial aminoglycoside exposure are temporarily relatively insensitive to the drug, so longer interdose intervals allow recovery of greater sensitivity. Thus, dosing to achieve higher peak drug levels less often would seem desirable. In several animal models of infection, greater efficacy and less oto- and nephrotoxicity have been associated with once daily dosing of aminoglycosides. Several clinical studies have indicated the importance of high peak serum aminoglycoside levels for efficacy. Limited studies of once daily dosing of these drugs in man have suggested that it is at least as favourable as conventional dosing. Nonetheless, despite the obvious advantages of cost and convenience and the theoretical and experimental indication that once daily dosing is advantageous, we need to test this concept in the clinical situation. Large prospective, randomized, double-blind, comparative studies of once daily and conventional dosing regimens in the treatment of various infections in different patient populations are required.

Aminoglycoside ototoxicity: a human temporal bone study.

OBJECTIVE: Hearing loss after aminoglycoside administration has been thought to result primarily from hair cell injury. The purpose of the study was to determine the potential for direct injury of spiral ganglion cells and hair cells in cases of documented human aminoglycoside ototoxicity. STUDY DESIGN: Retrospective case review. METHODS: The clinical course of two individuals with aminoglycoside ototoxicity are documented, including the details of administration of tobramycin and other ototoxic medication and serial audiograms. The temporal bones were processed, and the cochlear elements quantified. RESULTS: Histopathological study of the temporal bones from the individuals in the study demonstrated reduction of both ganglion cell and hair cell populations. Spiral ganglion cell loss was not necessarily subadjacent to areas of hair cell loss in cases of aminoglycoside ototoxicity. Instead, spiral ganglion cell reduction may be present in segments of the cochlea with normal-appearing hair cells. CONCLUSIONS: The study suggests that aminoglycoside antibiotics can injure spiral ganglion cells directly, as well as hair cells. Thus, the characteristic hearing loss of ototoxicity can result from degeneration of either cochlear element.

Schooling behavior of tadpoles: a potential indicator of ototoxicity.

Fish and tadpoles in schools use hair cells of their lateral line system to assess their position in relation to neighbors. This suggests that pharmaceutical agents that damage hair cells in the mammalian inner ear may also alter geometry in fish and tadpole schools. We used a computer-based image analysis system to examine the effect of the ototoxic aminoglycoside antibiotic, streptomycin, on school geometry for tadpoles of the African clawed frog Xenopus laevis. Tadpoles exposed to streptomycin in the surrounding water show a general tendency toward clumping, and an increase in the distance over which they orient parallel to neighbors, compared to controls. These behavioral responses appear in 18 min or less, and are evident in some tadpoles exposed to concentrations as low as 5 micrograms/ml. Results suggest that analysis of spatial relations in tadpole schools could serve as a method for rapidly detecting ototoxic potential of agents suspected of damaging hair cells.

Aminoglycoside antibiotics in the treatment of otologic infections.

Aminoglycoside antibiotics can be used successfully in the treatment of otologic infections caused by gram-negative bacteria. They can be particularly valuable, sometimes in combination with a beta-lactam antibiotic such as carbenicillin, in malignant external otitis, acute middle ear infections caused by gram-negative organisms, and central nervous system complications of cholesteatomas. On the basis of susceptibility tests and of the pharmacology of these drugs, we administer appropriate therapeutic doses of one of the following antibiotics: kanamycin, gentamicin, tobramycin, or amikacin. All of these drugs may be ototoxic and nephrotoxic.

Ganglion cell counts in the cochleae of patients with normal audiograms.

Spiral ganglion cells were counted in the right cochleae of 16 patients with normal audiograms and without a history of hearing deficit or other auditory symptoms. Total counts ranged from 29 802 to 38 352, with a mean of 33 623. There was no relationship between total counts and patient age or between total counts and length of either the cochlea or the spiral ganglion.

Bone-fill in guided tissue regeneration of periodontal defects.

The feasibility of regeneration and attachment of periodontal ligament and alveolar bone after surgical treatment of periodontal defects is documented in the literature. This article presents four cases of clinical and radiographic evidence showing apparent new attachment after root isolation with expanded polytetrafluoroethylene (PTFE) periodontal material, following the principle of guided tissue regeneration. Combination one-, two-, and three-wall angular bony defects of molars and incisors were exposed and root planed. A skirt of PTFE periodontal material was sutured into place and removed after 6 weeks in situ. Reductions in probed pocket depths and gain in bone-fill, as revealed by radiography, were achieved in every case. Maximum regeneration of alveolar bone was 6 mm in the two-wall angular defect of a first molar; minimum gain in bone height was 3 mm.

Optimal duration of treatment of urinary tract infections.

An examination of the pathogenesis of urinary tract infections leads to an understanding of the appropriateness of a broad range of treatment duration for infections with different stages of invasiveness. The ultimate short course, single-dose, is reviewed, and duration of therapy is discussed for infections in various clinical contexts and with various presentations.

Biphasic systemic anaphylactic reaction: three illustrative cases.

We report on three patients with early mild systemic reactions triggered by administration of rabies vaccine, immunotherapy with rye grass extract, or yellow jacket sting. After appropriate treatment, these early cutaneous and respiratory symptoms improved considerably, but then flared up three and one half to four hours later. All three patients had specific IgE antibodies against their offending allergen.