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Biomedical subjects

L Kramer

Publications and source records attributed to L Kramer.

At least 37 records · Page 2Linked to original sources

Immune recognition of genetically diverse simian T-cell lymphotropic virus type I isolates.

Nucleotide sequence analysis of selected regions of the gag, pol, env and pX genes of simian T-cell lymphotropic virus type I (STLV-I) strains indicated that African isolates were more closely related to human T-cell lymphotropic virus type I (HTLV-I) than Asian isolates. Despite these recent comparative studies on nucleotide sequence homology between HTLV-I and STLV-I isolates, only limited information is available regarding the influence of genetic differences on antigen-antibody recognition of distinct STLV-I strains. In this study, we demonstrated that sera from STLV-I-infected yellow baboons (Papio cynocephalus) reacted strongly with env gp62/68 from HTLV-I-infected cell lines MT-2 and C10/MJ. In contrast, sera from Japanese macaques (Macaca fuscata) naturally infected with Asian STLV-I had weak reactivity to env gp62/68 of these prototypic HTLV-I strains. Pst-1 restriction enzyme analysis of proviral DNA indicated that the baboon virus isolates were more closely related to HTLV-I than the Japanese isolates. These results indicate that nucleotide sequence diversity, correlates with variations in proviral restriction enzyme sites and antibody recognition of viral envelope proteins. These differences in immunoreactivity may have important implications for serologic diagnosis, as well as epidemiological and vaccine studies of STLV-I infection.

Animals

Maternal environment defines blood pressure and its response to troleandomycin in spontaneously hypertensive rats.

Relationship between family-3A cytochrome P-450-dependent (troleandomycin inhibitable) and maternal environmental-dependent systolic blood pressure (SBP) was investigated in spontaneously hypertensive rats (SHR). Adult SHR nursed by foster or natural SHR mothers had indistinguishable SBP. Troleandomycin reduced 50% of Wistar-Kyoto (WKY)-SHR strain difference in SBP. SHR having WKY foster mothers had SBP similar to troleandomycin-reduced SHR levels, which was unaffected by troleandomycin. The two components of SBP elevation appear identical. Because observations of others demonstrated that WKY fostered to SHR show no SBP increase, the maternally dependent/troleandomycin-sensitive component of SBP elevation may reflect epistatic interaction between genes determining maternal differences and offspring sensitivity, respectively.

Animals

Serial recording of sensory evoked potentials: a noninvasive prognostic indicator in fulminant liver failure.

Sensory evoked potentials are markedly changed in patients with fulminant liver failure. It is unknown, however, whether serial recordings of sensory evoked potentials provide useful prognostic informations for patient management in fulminant liver failure. Ninety recordings of bilateral median nerve-stimulated short- and long-latency sensory evoked potentials were performed in 25 patients with fulminant liver failure (9 patients spontaneously recovered and survived, 8 patients were referred to emergency liver transplantation and 8 patients died). In all nine survivors the cortical long-latency sensory evoked potential N70 peak was constantly detectable between 74 and 162 ms. In all eight patients who subsequently underwent liver transplantation and in seven of eight patients who died, loss of the N70 peak developed during the course of fulminant liver failure. In 4 of 15 patients who were selected for liver transplantation according to the King's College criteria, the N70 peak was constantly detectable. All four transplantation candidates spontaneously recovered and survived without transplantation. In contrast, eight patients never did fulfill the criteria for liver transplantation. Five of them with constantly detectable N70 peak recovered spontaneously. However, in the remaining three patients loss of the N70 peak developed, and they ultimately died. The probability of correct outcome prediction by sensory evoked potentials is superior to that based on clinical criteria alone (0.96 vs. 0.72). Therefore serial recording of sensory evoked potentials may help identify (a) a subgroup among liver transplantation candidates who may spontaneously recover without transplantation and (b) a subgroup of patients with severe brain dysfunction who should undergo early liver transplantation even though they do not fulfill King's College criteria.

Adolescent

Prenatal diagnosis of unilateral megalencephaly by real-time ultrasonography.

Unilateral megalencephaly is a rare anomaly of neuronal cell migration. We recently diagnosed this condition in a fetus at 20 weeks' gestation with ultrasonography and magnetic resonance imaging. The pregnancy was terminated and postmortem magnetic resonance imaging and autopsy confirmed the diagnosis. To our knowledge this represents the first case to be prenatally diagnosed with certainty.

Adult

Cognitive brain function in non-demented patients with low-grade and high-grade carotid artery stenosis.

Atherosclerotic stenosis of the carotid arteries decreases cerebral flow volume and perfusion, and may result in brain dysfunction. We studied the relationship between the degree of carotid artery stenosis and cognitive brain function in non-demented patients. Cognitive brain function was assessed in 76 patients with carotid artery stenosis (38 patients with low-grade stenosis of 50% or less, and 38 patients with high-grade stenosis of 75% or more) by recording of cognitive P300 auditory evoked potentials and trailmaking test. Results were compared to 70 age-matched healthy subjects. The P300 peak latency was prolonged in patients with high-grade carotid artery stenosis as compared to patients with low-grade stenosis (403 vs. 371 ms, P < 0.01, vertex; 400 vs. 370 ms, P < 0.01, frontal; means). Analysis of variance revealed that the degree of carotid artery stenosis is an independent predictor of prolonged P300 peak latency (P = 0.0001). P300 amplitude (12 vs. 15 microV, vertex; 13 vs. 15 microV, frontal, NS) and trailmaking test (60 vs. 54 s; NS) tended to be worse in the high-grade stenosis group. There was no difference in cognitive brain function between patients with low-grade stenosis and age-matched healthy subjects. Confirmed on sensitive cognitive P300 measurements, we conclude that (a) cognitive brain function is impaired in non-demented patients with high-grade carotid artery stenosis but unaffected in low-grade stenosis; and (b) cognitive brain dysfunction is directly related to the degree of carotid artery stenosis.

Aged

Patterns of fantasy play engagement across the transition to becoming a sibling.

Patterns of spontaneous dyadic fantasy play among 30 3- to 5-year-old first-born children who were becoming siblings were evaluated at two pre- and three post-birth intervals for its length, thematic content and social quality. Children who interacted more positively with their sibling played longer, engaged in fantasy play that was thematically relevant to becoming a sibling and had more positive interactions with best friends than low-sibling acceptance children. High-sibling acceptance children also experienced a suppression in fantasy immediately following their sibling's birth; thus, a temporary disruption in fantasy play may indicate adaptive coping.

Adaptation, Psychological

Evolving a legacy system: restructuring the Mendelian Inheritance in Man database.

Mendelian Inheritance in Man (MIM) is an encyclopedia of medical genetics that has been in electronic form for over 30 years. In its lifetime, MIM has undergone many organizational and software changes. In 1994, a major transition was made based on three basic principles: industry standards, open systems architecture, and extensibility. The resulting MIM database allows users to navigate to other genomic databases, permits the delivery of multimedia information, and improves the quality of data. The new MIM database also improved its administration because of 1) an internal format that enforces consistency; 2) a lower maintenance cost of software; and 3) a better ability to migrate MIM content. In addition, the new architecture will allow MIM easily to adopt emergent technologies as they mature.

Computer Systems

Early prediction of individual outcome after cardiopulmonary resuscitation.

Prediction of individual outcome after cardiopulmonary resuscitation is of major medical, ethical, and socioeconomic interest but uncertain. We studied the early predictive potency of evoked potential recording after cardiac arrest in 66 resuscitated patients who returned to spontaneous circulation but were unconscious and mechanically ventilated. Detailed long-latency and short-latency sensory evoked potentials were recorded and neurological evaluations were done 4-48 h after admission to intensive care. In all 17 patients with favourable outcome (cerebral performance categories 1 and 2) the cortical evoked potential N70 peak, a reliable measure of cortical function, was detected between 74 and 116 ms. In 49 patients with bad outcome (categories 4 and 5) the N70 peak was absent in 35 or found with a delay between 121 and 171 ms in 14 (p < 0.05 vs favourable outcome). Thus the predictive ability was 100% with cutoff of 118 ms. To confirm reproducibility and validity, repeated tracings, and linked-earlobe referenced techniques were done and gave similar results. Early recording of long-latency evoked potentials after cardiopulmonary resuscitation is highly predictive of outcome.

Adolescent

Energy metabolism in acute hepatic failure.

BACKGROUND: Conflicting data are available concerning energy metabolism in liver disease. Changes should be most pronounced in acute hepatic failure in which loss of 85% of liver cell mass is reported. Metabolic rate could be decreased due to impairment in liver mass but may also be increased as a result of systemic-mediator actions. To clarify this issue we studied energy metabolism in acute hepatic failure. METHODS: Energy metabolism was evaluated by indirect calorimetry in 12 patients with acute liver failure and 22 sex-, age-, and body size-matched healthy individuals. In controls and 5 patients, studies were performed in the postabsorptive state; the remaining 7 patients received glucose at a rate of 8 mumol/kg body weight.min to prevent hypoglycemia. RESULTS: Resting energy expenditure was increased in acute liver failure compared with healthy controls (5.1 +/- 0.14 kJ.min-1 x 1.73 m-2 vs. 3.97 +/- 0.08 kJ.min-1 x 1.73 m-2; mean +/- SEM; P < 0.001). Respiratory quotient and oxidation rates for major fuels were not different between the total patient-group and controls. In patients without glucose supply, energy derived from fat was higher and from carbohydrate lower than in healthy controls and patients with glucose supply. CONCLUSIONS: Energy expenditure is increased in acute liver failure. Altered substrate oxidation can be normalized by glucose supply.

Adult

Epizootic gastritis associated with gastric spiral bacilli in cheetahs (Acinonyx jubatus).

An outbreak of vomiting in a group of captive cheetahs (Acinonyx jubatus) was investigated, and histologic examination revealed chronic gastritis characterized by infiltration of lymphocytes and numerous plasma cells and epithelial erosions. Lymphoid follicles, globule leukocytes, scattered neutrophils, and (in one animal) abscessed gastric glands were inconsistent findings. In addition, necropsy of three cheetahs revealed gastric mucosal hyperplasia. Two kinds of bacteria were identified in the stomachs of infected cheetahs. Numerous long, tightly coiled motile Gastrospirillum-like organisms were seen in gastric mucus and in Warthin-Starry-stained sections of mucosa. These bacteria could not be cultured but were transmitted to conventional mice in homogenates of gastric mucosa from infected cheetahs. Ultrastructural examination revealed helical filaments on some of these bacteria. In addition, a smaller Helicobacter sp. was isolated. This organism could be cultured in vitro under microaerophilic conditions. One or both of these bacterial species was probably responsible for the gastritis in these cheetahs.

Acinonyx

Effect of immunoglobulin administration on blood rheology in patients with septic shock.

The hemorrheological determinants plasma fibrinogen, plasma viscosity, red cell aggregation, and hematocrit were studied in 11 patients before and 4 and 24 hr after a 15 g immunoglobulin infusion to assess the effect of intravenous immunoglobulin administration on blood rheology in septic shock. Four hr after the immunoglobulin administration, plasma fibrinogen decreased significantly [472 (175-950) vs. 522 (182-1,050) mg/dl before administration; median (range); P < 0.01]; after 24 hr, plasma fibrinogen tended to increase again [501 (185-980); n.s.]. No changes were seen in plasma viscosity, red cell aggregation, hematocrit, and coagulation status 4 and 24 hr after immunoglobulin administration. In patients with septic shock, intravenous immunoglobulin administration leads to a decrease in plasma fibrinogen, whereas plasma viscosity and red cell aggregation remain unaffected. The explanation for the decrease in fibrinogen remains speculative.

Adult

MR imaging of diplomyelia.

We present an unusual case of duplication of the fifth lumbar vertebra and sacrum in a 6-year-old boy. The spinal cord was also duplicated and tethered by bone spurs bilaterally. The imaging features and the embryological basis of diplomyelia are discussed.

Abnormalities, Multiple

Gastric spiral bacilli in captive cheetahs.

Two kinds of gastric spiral bacilli were identified in the stomachs of captive cheetahs with naturally occurring gastritis. One type was morphologically similar to 'Gastrospirillum hominis'. This organism could not be cultured in vitro. Some of these bacteria had superficial helical filaments, and others did not. The other type was morphologically, biochemically, and bacteriologically similar to Helicobacter pylori. This organism is most likely a new species of Helicobacter. One or both of these bacteria may have been responsible for the gastritis seen in these cheetahs.

Acinonyx