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Biomedical subjects

D Krieger

Publications and source records attributed to D Krieger.

At least 91 records · Page 5Linked to original sources

Bacteriological data on a prospective multicenter study of the effect of two different regimens for selective decontamination in patients with acute leukaemia.

In this paper we described the results of bacteriological monitoring of oropharynx and stool samples from granulocytopenic patients with leukaemia who received oral infection prophylaxis with two different regimens for selective decontamination of the digestive tract. Patients were prospectively randomized either into a group receiving non-absorbable antimicrobial drugs for selective decontamination (polymyxin and neomycin: group A) or into a group receiving polymyxin and co-trimoxazole (group B). The oropharynx was, or became, free of gram-negative bacilli within one week of treatment in 94% and 90%, respectively, of the patients in group A and group B. The stool samples were, or became, negative after the same treatment interval in 91% and 80%, respectively, of the two patient groups. Antibiotic therapy during selective decontamination treatment significantly increased the incidence of positive cultures from the oropharynx and stools. The sensitivity of the gram-negative bacilli isolated during selective decontamination treatment to the drugs administered did not influence the average response to treatment. Both resistant and sensitive gram-negative bacteria appeared to disappear from the patients' samples, mostly within a week, without the need to adjust the selective decontamination treatment. Yeasts behaved in almost the same way as gram-negative bacilli. All patients received oral amphotericin B; some patients occasionally yielded oropharyngeal or faecal cultures which were positive for yeasts.

Acute Disease↗

Prevention of infection in acute leukemia: a prospective randomized study on the efficacy of two different drug regimens for antimicrobial prophylaxis.

In a prospective study patients with acute leukemia undergoing remission induction therapy were randomized to receive either a regimen of non-absorbable antimicrobial drugs (colistin and neomycin) or of absorbable and non-absorbable drugs (trimethoprim-sulfamethoxazole [TMP-SMZ] and colistin) for antibacterial prophylaxis. For antifungal prophylaxis patients in both groups were given oral amphotericin B. The proportion of patients without acquired infections and the median of study time to the first acquired infection did not differ significantly between the two treatment groups (p greater than 0.05). Septicemias occurred in nine out of 49 recipients of colistin and neomycin and in one out of 56 patients receiving TMP-SMZ and colistin (p = 0.03). Localized infections and fever episodes without proven infections were equally distributed between the two groups. The incidence of febrile days and of days on parenteral antibiotic therapy was significantly lower in the group given TMP-SMZ and colistin (p less than 0.05). The duration of severe granulocytopenia and thrombocytopenia did not differ significantly between the two groups (p greater than 0.05).

Adolescent↗

Monitoring therapeutic efficacy of decompressive craniotomy in space occupying cerebellar infarcts using brain-stem auditory evoked potentials.

Brain-stem auditory evoked potentials (BAEPs) have been used to gauge effects of brain-stem dysfunction in humans and animal models. The purpose of this study was to evaluate the usefulness of BAEP in monitoring patients undergoing decompressive surgery of the posterior fossa for space occupying cerebellar infarcts. We report on serial BAEP recordings in 11 comatose patients with space occupying cerebellar infarcts undergoing decompressive craniotomy. BAEP studies were performed within 12 h after admission, 24 h following surgery and prior to extubation. BAEP signals were analyzed using latency determination and cross-correlation. Following surgery, 9 patients regained consciousness; 2 patients persisted in a comatose state and died subsequently. BAEP interpeak latency (IPL) I-V assessed prior to surgery exceeded normal values in all patients in whom it could be reliably measured (N = 9). Following decompressive surgery BAEP wave I-V IPL normalized in 5 patients, but remained prolonged despite dramatic clinical improvement in 4 patients. We prospectively computed the coefficient of cross-correlation (MCC) of combined ipsilateral BAEP trials after right and left ear stimulation. In all patients increasing MCC was associated with clinical improvement. Unchanging or decreasing MCC indicated poor outcome. We conclude that serial BAEP studies are an appropriate perioperative monitoring modality in patients with space occupying cerebellar infarcts undergoing decompressive surgery of the posterior fossa. Our study suggests advantages of cross-correlation analysis as an objective signal processing strategy; relevant information can be extracted even if BAEP wave discrimination is impossible due to severe brain-stem dysfunction.

Acoustic Stimulation↗

Mycetoma due to Exophiala jeanselmei and Mycobacterium chelonae in a 73-year-old man with idiopathic CD4+ T lymphocytopenia.

Exophiala jeanselmei and Mycobacterium chelonae were isolated from cutaneous nodules in a 73-year-old man with mycetoma of the right lower leg. Further evaluation revealed CD4+ lymphocytopenia without evidence of HIV infection. Antibodies to HIV 1/2, p24 antigen and HIV 1/2 (PCR) and reverse transcriptase activity were not detectable. The patient was not a member of any HIV risk group. He had not previously undergone therapy or suffered from immunodeficiency. This case clearly demonstrates that infections with opportunistic moulds and/or atypical mycobacteria should be taken into consideration not only in patients with classical immundeficiency diseases but also in apparently healthy patients because infection with these agents can be the first sign of underlying immunodeficiency.

Aged↗

Comparison of orthogonal search and canonical variate analysis for the identification of neurobiological systems.

In this paper, we investigate two general methods of modeling and prediction which have been applied to neurobiological systems, the orthogonal search (OS) method and the canonical variate analysis (CVA) approach. In these methods, nonlinear autoregressive moving average with observed inputs (ARX) and state affine models are developed as one step predictors by minimizing the mean-squared-error. An unknown nonlinear time-invariant system is assumed to have the Markov property of finite order so that the one step predictors are finite dimensional. No special assumptions are made about model terms, model order or state dimensions. Three examples are presented. The first is a numerical example which demonstrates the differences between the two methods, while the last two examples are computer simulations for a bilinear system and the Lorenz attractor which can serve as a model for the EEG. These two methods produce comparable results in terms of minimizing the mean-square-error; however, the OS method produces an ARX model with fewer terms, while the CVA method produces a state model with fewer state dimensions.

Electroencephalography↗

Real time signal processing in the clinical setting.

We routinely use a variety of real time signal acquisition, enhancement, and display techniques in the operating room to provide the surgeon with functional information. This enables reduction of surgical morbidity in cases which present a significant risk to the nervous system. Here we present regression based signal processing algorithms which produce considerable signal-to-noise-ratio enhancement with corresponding reduction in the time required to obtain an interpretable neurophysiological signal. We also present the approach we have applied to fault tolerance and distributed data display for our workstation cluster environment.

Algorithms↗