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Biomedical subjects

L Kaufman

Publications and source records attributed to L Kaufman.

At least 127 records · Page 7Linked to original sources
PubMed1994

MRI of a silicone breast implant surrounded by an enlarging hemorrhagic collection.

MRI yields cross-sectional image acquisition in multiple planes with very high contrast resolution. Additionally, in MRI of the breast, evaluation of the entire implant is possible. Not only is MRI very sensitive to loss of implant integrity and rupture, but also MRI can evaluate and characterize adjacent fluid collections or soft-tissue masses. Anatomic relationships of abnormalities and normal structures are well seen. In some situations, MRI may offer clinically relevant information not adequately addressed by other imaging modalities.

Breast↗
PubMed1994

Comparative evaluation of chemiluminescent DNA probe assays and exoantigen tests for rapid identification of Blastomyces dermatitidis and Coccidioides immitis.

Chemiluminescent DNA probe (Accuprobe) assays developed by Gen-Probe, Inc. (San Diego, Calif.), for the rapid identification of Blastomyces dermatitidis and Coccidioides immitis were evaluated and compared with the exoantigen test by using 74 mycelial cultures of B. dermatitidis and 72 mycelial cultures of C. immitis. Seventeen isolates of the dimorphic pathogen Paracoccidioides brasiliensis were included because of their gross morphologic and antigenic relatedness to B. dermatitidis. The heterologous fungi, namely, species of Chrysosporium, which are often confused with B. dermatitidis, and species of Malbranchea, which morphologically resemble C. immitis, were tested. All 74 of the B. dermatitidis mycelial isolates were correctly identified by the Accuprobe assay for B. dermatitidis within 2 h. However, the B. dermatitidis probe cross-hybridized with rRNA extracts of 10 of the 17 P. brasiliensis isolates, misidentifying them as B. dermatitidis. All 72 of the C. immitis isolates were identified correctly with the C. immitis probe. None of the other heterologous fungi belonging to Chrysosporium spp., Malbranchea spp., Onychocola canadensis, and Geotrichum sp. were cross-reactive with the B. dermatitidis and C. immitis probes. The exoantigen tests specifically identified 74 B. dermatitidis, 72 C. immitis, and 17 P. brasiliensis isolates within 48 to 72 h and differentiated the related heterologous fungi from the three dimorphic fungal pathogens.

Animals↗
PubMed1994

Fiberoptic evaluation of the nasal and nasopharyngeal anatomy in children with snoring.

In this prospective study, fiberoptic examinations of the nasal cavity and nasopharynx were performed in 162 children with snoring and compared with similar examinations performed in 211 children without snoring. Our study aimed to determine a correlation between snoring and measured parameters of nasal and nasopharyngeal anatomy including the size of the adenoid tissue. Results have confirmed significant evidence that adenoid hyperplasia is the commonest etiologic factor in children with snoring (p < .001). In addition, an important statistical relevance of mouth breathing in snoring was demonstrated (p < .001). It seemed that mouth breathing is a basic condition in children's snoring. It is essential to both confirm that mouth breathing occurs, and then, to institute an appropriate treatment as a therapeutic approach for children with snoring. The introduction of the flexible fiberscope in the fields of pediatric examination of the nasal cavity and nasopharynx has proved to be of great clinical value.

Adenoids↗
PubMed1993

A technique for assessment of bone marrow composition using magnetic resonance phase interference at low field.

In disorders which involve the bone marrow, the fat/water ratio of the marrow is often an indicator of the progress of disease. A noninvasive method of monitoring this ratio in bone marrow could be clinically useful. We have investigated a method of bone marrow assessment, using magnetic resonance imaging at low field (0.064 Tesla). The method has been tested using calibrated phantoms; we also present results from normal human subjects.

Adult↗
PubMed1993

Etiology of the sexual dimorphism in renal peripheral benzodiazepine receptor response to stress in rats.

A sexual dimorphism in stress-induced alterations in renal peripheral benzodiazepine receptors (PBR) was recently reported. The present paper includes five experiments examining the etiology of this sex difference. Surgical removal of ovaries and testes was ineffective in altering the renal PBR stress response in both male and female rats. A diurnal variation in the sexual dimorphism was observed; the difference was seen in the early part of the light cycle, while the two sexes were indistinguishable at the end of the light cycle. Finally, based on recent data indicating the importance of the renin-angiotensin system in the stress-induced decrease in renal PBR, we examined both stress-induced plasma renin activity and renal PBR reactivity to exogenous angiotensin II (AII) administration in both sexes. Female rats show both an attenuated elevation of plasma renin levels in response to inescapable shock stress and a reduced PBR response to AII administration in comparison to males. The present data indicate that the renin-angiotensin system may be a critical factor in the sexual dimorphism in the renal PBR response to stress. The possibility of this difference in the renin-angiotensin system contributing to sex differences in susceptibility to escape deficits following inescapable shock is entertained. The implications for these findings regarding the physiological function of the PBR are also discussed.

Angiotensin I↗
PubMed1993

Treatment and serological studies of an Italian case of penicilliosis marneffei contracted in Thailand by a drug addict infected with the human immunodeficiency virus.

A case of disseminated penicilliosis marneffei, the first to be diagnosed in Italy, is described in a male HIV-positive drug addict. The patient had visited Thailand several times in the two years prior to his hospitalization. The presenting signs were fever, productive cough, facial skin papules and pustules, nodules on both thumbs and oropharyngeal candidiasis. Penicillium marneffei was isolated from a series of blood specimens with the lysis centrifugation procedure. Septate, yeast-like cells were observed in histological sections of the nodules and sputum smears. The patient was treated for 6 weeks with amphotericin B (total dosage 1,400 mg) and flucytosine (150 mg/kg/die) for the first 3 weeks. Prompt clinical improvement and sterilization of all biological specimens were attained. Itraconazole was administered as maintenance therapy (400 mg/die for the first month and 200 mg afterward). During the follow-up period, no relapse was observed. The patient, however, did succumb to a variety of non-mycotic infections and died nine months after start of therapy. At autopsy, P. marneffei was not detected in his tissues. Serological studies were performed with a micro-immunodiffusion procedure using a mycelial culture filtrate antigen of P. marneffei. Sera taken early in the course of the disease gave positive antibody reactions. Whereas sera taken 3-5 months following therapy were negative. All known cases of penicilliosis marneffei in bamboo rats and in humans among the inhabitants and visitors to the endemic areas of P. marneffei in South East Asia and Indonesia are summarized.

AIDS-Related Opportunistic Infections↗
PubMed1993

Magnetic source imaging based on the minimum-norm least-squares inverse.

The flow of ionic currents within the neurons of cerebral cortex produces a magnetic field that can be detected outside the human scalp. The dominant contribution is attributed to pyramidal cells, which are preferentially oriented perpendicular to the cortical surface. In general, it is not possible to deduce a unique representation of the spatial configuration of these cortical sources from a measurement of their field pattern alone. However, accurate a priori knowledge of the geometry of the underlying cerebral cortex makes it possible to infer the spatial configuration of these transcortical current sources, moment by moment, without imposing a simplified model such as a small set of current dipoles. To achieve such a realistic magnetic source image, we have introduced what we call the "Minimum-Norm Least-Squares Inverse" (MNLS inverse) for the magnetic problem. The MNLS inverse provides the least residual error in accounting for the measured field pattern, with a source current distribution having minimum power. An extension of this procedure provides an inverse solution for average field power, as opposed to field per se. This makes it possible to define spatial configurations of spontaneous cortical activity not phase-locked to a sensory stimulus. Rhythmic activity such as the occipital alpha rhythm is one example. Thus, it is possible to determine spatial patterns of enhanced or suppressed cortical rhythms that accompany cognitive processes and some pathological conditions. This paper provides the necessary background for understanding these recent developments, as well as examples of how they might be used.

Brain↗
PubMed1993

Imaging regional changes in the spontaneous activity of the brain: an extension of the minimum-norm least-squares estimate.

This paper describes methods for inferring mathematically unique local distributions of primary cortical current that underly changes in the average pattern of power of the ongoing ("spontaneous") extracranial magnetic field of the brain. In previous work we demonstrated that mathematically unique solutions to the inverse problem are possible for current sources of the brain's field, without assuming a small set of current dipoles as a source model. In principle, it is possible to locate and delineate patterns of current of any configuration. In practice this approach applies to synchronized neuronal activity, e.g., activity which is known to underly average evoked or event-related brain responses. This paper extends that approach to local changes in incoherent activity, e.g., activity yielding fields or potentials that tend to be self-cancelling when averaged over time. This includes the spontaneous brain activity normally treated as background noise when it accompanies event-related responses. We demonstrate that local changes in this ongoing incoherent activity may also be uniquely delineated in space and time. The solution is a covariance matrix characterizing activity across an image surface. Its diagonal elements represent the spatial pattern of mean current power. Evidence is reviewed indicating that the distribution of the brain's magnetic field, due to both its synchronized and incoherent neural activity, is affected by early sensory-perceptual processes and by higher cognitive processes. Hence, in principle, the ability to delineate both kinds of sources in space and time makes it possible to form more comprehensive dynamic functional images of the human brain.

Brain↗
PubMed1993

Radioiodine turnover studies as a means to predict stable intrathyroidal iodine stores and comments upon its use in the diagnosis and treatment of hyperthyroidism.

Stable intrathyroidal iodine pool (ITI) is known to affect both diagnosis and treatment of hyperthyroidism. Very few laboratories have facilities to measure ITI. In our department x-ray fluorescence was routinely used for more than 15 years. We report here that it is possible to predict the ITI by means of classic 131I turnover studies and at least distinguish hyperthyroid patients with a small ITI pool ("small pool" patients) from those with a large ITI. It could be shown from a retrospective study (selected hyperthyroid patients, n = 118) that (1) in our area the small pool patients represent the majority as opposed to the situation in the United States, (2) that there was a highly significant negative correlation (p < 0.001) between the PB 131I at 24 h and ITI, and (3) that the non-small pool patients were more resistant to treatment than the others. In a prospective study of 91 consecutive patients with a thyroid problem, it was be shown that in the euthyroid group no correlation could be found between ITI on the one hand and 131I uptake and PB 131I at 24 h or urinary iodine on the other. In the hyperthyroid patients a strong negative correlation was again found between ITI and PB 131I (p < 0.001), stronger than with 131I uptake p = 0.093). No correlation existed with urinary iodine. In a second prospective study of hyperthyroid patients (n = 56), it was confirmed that measuring the PB 131I could classify hyperthyroid patients into non-small pool and small pool subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1993

Disseminated atypical blastomycosis in two patients with AIDS.

Two men with AIDS developed fungal infections and subsequently died as a result of dissemination of the fungal infection. Findings obtained by histologic examination, serological studies, and cultures suggested that the infections were caused by Blastomyces dermatitidis. Tissue sections showed polymorphic yeast-like cells 5-20 microns in diameter (some with broad and others with narrow single- or multiple-based buds), small yeasts, and hyphal elements. The exoantigen K positivity and exoantigen A negativity of one of the isolates indicated that the fungus was more like an African than a North American serotype.

AIDS-Related Opportunistic Infections↗
PubMed1993

Mycobacterium simiae infection in Israeli patients with AIDS.

Mycobacterium simiae is an environmental organism that has rarely been associated with human disease. In Israel M. simiae is frequently isolated from clinical specimens, and it usually colonizes damaged lungs. Until now, only two cases of AIDS patients with M. simiae infection have been reported, and these patients were coinfected with Mycobacterium avium complex. Two Israeli patients with AIDS complicating hemophilia developed prolonged fever that was unresponsive to therapy with broad-spectrum antibiotics. One of them had cavitary pulmonary infiltrates. M. simiae was isolated from blood in both cases and from sputum and bone marrow in one case. The identity of the mycobacterium was confirmed at three reference laboratories. Both patients died of the infection. Thus, the possibility of M. simiae infection should be considered for AIDS patients who live in areas where this mycobacterium is prevalent.

AIDS-Related Opportunistic Infections↗
PubMed1993

Evaluation of truncated readout-echo MR images obtained at 0.35 T.

It is possible to acquire a truncated echo, in which part of the information at the beginning or end of the echo is missing, and to restore the missing information by conjugation. This process was shown by means of edge spread function in phantoms and brain images in volunteers to introduce little, if any, degradation of image quality and can be used to improve sequence efficiency or to shorten echo time.

Brain↗
PubMed1993

Differentiation of silicone gel from water and fat in MR phase imaging of protons at 0.064 T.

The authors present a method of identifying silicone at magnetic resonance (MR) imaging based on its chemical shift. The method relies on phase images reconstructed from a gradient-recalled-echo sequence that has an echo time chosen to maximize the phase offsets between water, fat, and silicone. Results from studies at 0.064 T of both phantoms and human subjects are presented. This technique was useful in identifying extracapsular silicone and may be applicable at other field strengths.

Adipose Tissue↗
PubMed1993

Conjugation and hybrid MR imaging.

PURPOSE: To evaluate the use of conjugation with hybrid magnetic resonance imaging techniques in order to reduce artifacts from inconsistencies introduced by T2 decay. MATERIALS AND METHODS: Two phantoms containing either oil or water were used to study edge spread function (ESF) and signal-to-noise ratio (S/N) for three hybrid acquisition strategies (low pass, high pass, and ramp) in which a full set was acquired or with partial acquisition and conjugation. RESULTS: With half the echoes providing coverage of the same amount of k space, signal inconsistencies were reduced by a factor of at least e. Conjugation improved ESF degradation, and sequence efficiency increased by over 50%, which compensated for a loss in S/N. CONCLUSION: The time saved with conjugation can be used to nearly double the number of sections acquired for a given repetition time (TR) or to obtain two simultaneous echoes instead of one, with reduction of artifacts. Alternatively, the imaging time can be nearly halved for a given TR and number of sections.

Artifacts↗
PubMed1993

Prevention of adjustment disorders and anticipatory nausea secondary to adjuvant chemotherapy: a double-blind, placebo-controlled study assessing the usefulness of alprazolam.

PURPOSE AND METHODS: Although a high prevalence of adjustment disorders and anticipatory nausea secondary to adjuvant chemotherapy (CT) has been reported, little has been done to develop strategies to prevent these problems. A double-blind, placebo-controlled study was therefore designed to assess the usefulness of adding low-dose alprazolam (0.5 mg to 2 mg per day) to a psychologic support program including progressive relaxation training designed to prevent the aforementioned conditions. Fifty-seven women undergoing adjuvant CT for stage II primary breast cancer agreed to participate in the assessment, which was conducted at four time points: before starting CT, 6 weeks after CT, before the fourth CT, and after the fourth CT. The Hospital Anxiety and Depression Scale (HADS), Montgomery and Asberg Depression Rating Scale (MADRS), Hamilton Anxiety Scale (HAS), Revised Symptom Checklist (SCL-90-R), Morrow Assessment of Nausea and Emesis (MANE), and World Health Organization (WHO) grading of acute and subacute toxicities were used to compare the alprazolam (AA) and placebo (PA) arms of the study. RESULTS: At the second evaluation, the results showed a higher rate of anticipatory nausea (18% v 0%) in the PA compared with the AA arm (P = .038). These differences were no more significant at each of the further assessments. Significant differences were found for the intake of hypnotics at each assessment visit, with the rate of hypnotic users being significantly higher in the PA (19%) compared with the AA (0%) arm at the fourth assessment (P < .05). Anxiety and depression scores of self- and observer-report were similar in the two arms. A significant relationship was found between the development of anticipatory nausea and the self-report of anxiety and depression score measured by HADS at baseline. The average HADS total score at baseline was 15.33 (SD = 6.56) for patients who developed anticipatory nausea and 11.23 (SD = 6.67) for other patients. CONCLUSION: The adjunct of alprazolam to a psychologic support program delays the occurrence of anticipatory nausea and controls sleeping problems secondary to adjunct CT. Although studies are needed to improve the efficacy reported here, physicians may already consider the use of alprazolam for cancer patients undergoing CT.

Adjustment Disorders↗
PubMed1993

Cryptococcus neoformans var. gattii in India.

An examination of 18 clinical isolates of Cryptococcus neoformans from India revealed that 15 belonged to C. neoformans var. neoformans (serotype A = 13 isolates, serotype AD = two isolates) and three belonged to C. neoformans var. gattii (serotype B). This is the first documented record of the var. gattii and serotype AD of the var. neoformans occurring in India.

Cryptococcosis↗