Biomedical subjects

A Bergman

Publications and source records attributed to A Bergman.

At least 91 records · Page 5Linked to original sources

PubMed1997

CT with the hepatocyte-specific contrast medium FP 736-04 in an experimental model of liver steatosis.

PURPOSE: To investigate whether liver uptake of the iodinated hepatocyte-specific lipid emulsion FP 736-04 is altered by fatty infiltration of the liver. MATERIAL AND METHODS: Fatty infiltration of the liver was induced in female Sprague-Dawley rats by an intraperitoneal injection of L-ethionine preceded by 15 h of food withdrawal. CT of the liver was performed before and 24 h after the administration of L-ethionine and, in addition at the latter time point, after an i.v. injection of 1.0 ml/kg b.w. of FP 736-04. A control group was subjected to the same CT examination protocol. RESULTS: Intraperitoneal administration of L-ethionine caused liver steatosis, as established by liver triglyceride analysis, leading to a significant decrease in the liver attenuation, from 69.2 +/- 2.4 to 27.8 +/- 12.0 HU. The uptake of FP 736-04 by the fatty liver was significantly reduced, yielding a maximum enhancement of 22.3 +/- 7.9 HU as compared to a value of 32.3 +/- 5.0 HU in the control group. CONCLUSION: Enhancement by FP 736-04 was reduced in the steatotic liver compared with the normal liver. It remains to be established whether this degree of enhancement is sufficient for reliable lesion detection.

Animals↗

PubMed1997

CT with different doses of the hepatocyte-specific contrast medium FP 736-03. Evaluation in a nude-rat model of experimental metastases.

PURPOSE: To study the dose-response relationship in FP 736-03 (48 mg I/ml), hepatocyte-specific contrast medium for CT of the liver. MATERIAL AND METHODS: A nude-rat model of experimental hepatic metastases was used. CT of the liver was performed before and after i.v. injection of FP 736-03 at 4 different doses: 0.25, 0.5, 1.0 and 2.0 ml/kg b.w. Attenuation in the normal liver parenchyma and in the metastases was measured and plotted as a function of time. RESULTS: The enhancement of the normal liver parenchyma increased in the dose range studied. No increase was found in the metastases: the attenuation here remained constant during the observation period. The maximum enhancement values at doses of 0.25, 0.5, 1.0 and 2.0 ml/kg b.w. were (mean +/- SD) 13.5 +/- 2.7, 30.1 +/- 4.2, 33.2 +/- 4.5 and 59.7 +/- 13.1 HU respectively.

Adenocarcinoma↗

PubMed1997

Microsatellite genetic distances with range constraints: analytic description and problems of estimation.

Statistical properties of the symmetric stepwise-mutation model for microsatellite evolution are studied under the assumption that the number of repeats is strictly bounded above and below. An exact analytic expression is found for the expected products of the frequencies of alleles separated by k repeats. This permits characterization of the asymptotic behavior of our distances D1 and (delta mu)2 under range constraints. Based on this characterization we develop transformations that partially restore linearity when allele size is restricted. We show that the appropriate transformation cannot be applied in the case of varying mutation rates (beta) and range constraints (R) because of statistical difficulties. In the special case of no variation in beta and R across loci, however, the transformation simplifies to a usable form and results in a distance much more linear with time than distances developed for an infinite range. Although analytically incorrect in the case of variation in beta and R, the simpler transformation is surprisingly insensitive to variation in these parameters, suggesting that it may have considerable utility in phylogenetic studies.

Computer Simulation↗

PubMed1997

Attentional functioning in schizotypal personality disorder.

OBJECTIVE: Previous research has shown biological, phenomenological, and cognitive similarities between schizophrenic patients and individuals with schizophrenia-related personality disorders and features. Evidence further suggests that of these common dysfunctions, abnormal attention is one of the most promising indicators of a biological susceptibility to schizophrenia-related disorders. Although attentional dysfunctions have been reliably detected in schizophrenic patients as well as in a variety of populations at risk for schizophrenia, few studies have investigated attention in clinical patients with schizotypal personality disorder. In this study, the extent of attentional impairment was assessed in subjects with schizotypal personality disorder, normal comparison subjects, patients with other personality disorders, and schizophrenic patients. METHOD: Thirty subjects with schizotypal personality disorder, 35 subjects with other personality disorders (i.e., clinic patients with non-odd cluster personality disorders), 36 subjects with schizophrenia, and 20 comparison subjects who did not meet criteria for any axis I or axis II disorder participated in this study. All subjects were diagnosed according to DSM-III criteria. Attention was assessed by using the Continuous Performance Test, Identical Pairs Version. RESULTS: Analyses indicated that subjects with schizotypal personality disorder, like schizophrenic subjects, performed significantly worse than comparison subjects on both the verbal and spatial tasks of the Continuous Performance Test, Identical Pairs Version. In contrast, patients with other personality disorders performed similarly to comparison subjects across conditions. CONCLUSIONS: These results suggest that patients with schizotypal personality disorder are impaired in their attentional functioning relative to normal comparison subjects and that they display deficits that are similar to the pattern characterizing schizophrenic patients.

Adult↗

PubMed1997

Assessing axis II disorders by informant interview.

Although much of personality disorder research depends on diagnostic data obtained directly from patients, this approach has rarely been compared to interviews with knowledgeable informants. The purpose of this study was to determine the diagnostic agreement between these two assessment methods, as well as their relative contribution to the formulation of consensus diagnoses. Sixty-two psychiatric patients were assessed directly with the Structured Interview for DSM-III Personality Disorders (SIDP), and were asked to nominate an informant--either a family member or friend--to provide information about the patient in an interview with the same instrument. Informant interviews were conducted blind to patient-based information whenever feasible, and diagnostic consensus was achieved by an independent review of all available data by a senior clinician. Diagnostic agreement between patient-based and informant-based personality disorder interview was poor, confirming the findings of two previous studies. Information obtained from patients tended to be given greater weight in formulating consensus diagnoses than information provided by informants. However, about one quarter of diagnostic disagreements were resolved in favor of informant-based information. In contrast to a previous study, the inclusion of informant information did not appear to reveal greater psychopathology in patients. We conclude that supplementing direct patient interview with data provided by a knowledgeable informant appears to enhance the resolution of some personality disorder diagnoses. The utility of informant interviews may depend on an analysis of the costs and benefits of this additional degree of descriptive refinement.

Adult↗

PubMed1997

Hepatocyte-specific contrast media for CT. An experimental investigation.

CT is an important technique in liver imaging. To improve the detection of focal liver lesions the use of non-specific, water-soluble contrast media (CM) is mandatory. However, even with use of these CM the sensitivity in tumour detection is low. In the development of liver-specific CM, the majority of the agents have been targeted to the reticuloendothelial system (RES). The clinical use of RES-specific contrast agents has been hampered by frequent adverse reactions, and a new concept whereby the CM is taken up by the hepatocytes has been developed as an alternative. Such a CM is taken up by normal liver parenchyma but not by tumour cells, enhancing the difference between normal and pathological tissue, and therefore improving the diagnostic sensitivity. In the present investigation, FP 736-03 and FP 736-04, two hepatocyte-specific lipid emulsions, have been studied using animal models. In normal liver parenchyma dose-dependent enhancement was found, whereas in tumour tissue of experimental liver metastases and hepatocellular carcinoma, no enhancement was noted. The virtually unchanged attenuation in tumour tissue meant that the liver-to-lesion contrast increased steadily during the observation period. In an attempt to establish the relationship between enhancement and tumour detection, the accumulated doses of FP 736-04 were used. Increasing accuracy in the diagnosis of liver metastases was found up to an enhancement level of 30 HU. A further increase yielded similar detection rates, but a higher proportion of false-positive results. Comparison with iohexol was rendered difficult by the occurrence of image artefacts when this CM was used. However, FP 736-03 proved superior to both native and iohexol-enhanced CT for detection of hepatic metastases. The efficacy of FP 736-04 was also studied in diseased hepatic parenchyma. In cases of fatty liver infiltration, enhancement by FP 736-04 was significantly reduced as compared with normal controls. The degree of enhancement observed in cirrhotic livers did not differ significantly from that in the controls. These preclinical investigations have shown that the hepatocyte-specific lipid emulsions FP 736-03 and FP 736-04 improve the diagnostic accuracy of focal liver lesions as compared to native and water-soluble CM-enhanced CT. FP 736-04 is taken up by diseased liver parenchyma. However, the detection of malignancy in steatotic and cirrhotic livers has not yet been studied with use of this CM.

Animals↗

PubMed1996

Toxicity of 2,4,4'-trichlorobiphenyl in rats following 90-day dietary exposure.

The toxicity of 2,4,4'-trichlorobiphenyl (PCB 28) was investigated in rats after a 90-d dietary exposure. Groups of 10 male and 10 female weanling Sprague-Dawley rats were administered PCB 28 in the diet at 0, 0.05, 0.50, 5.0, or 50.0 ppm for 13 wk. Growth rate and food consumption were not affected by treatment, and no clinical signs of toxicity were observed. Mottled liver was noted in both control and PCB-treated males, but was found with increased incidence in the highest treatment group. Increased urinary ascorbic acid and hepatic microsomal ethoxyresorufin O-deethylase activity were observed in the 50.0 ppm group of both sexes. The vitamin A content in liver, lung, and kidney was not significantly affected by treatment. Analysis of brain biogenic amines showed a decreased dopamine concentration in the substantia nigra region of female rats receiving 0.5 ppm PCB 28 and higher doses. Female rats appeared to be more sensitive than males to the neurochemical effects of PCB 28. Dose-dependent histologic changes were observed in the thyroid and liver, with biologically significant changes occurring at 5.0 ppm and above. Based on these data, the no observable-adverse-effect level (NOAEL) for this PCB congener was considered to be 0.5 ppm in diet or 36 micrograms/kg body weight/d.

Administration, Oral↗

PubMed1996

Periurethral collagen implant: ultrasound assessment and prediction of outcome.

The objective of this study was to identify sonographic parameters that could predict successful outcome in women after periurethral collagen implant. Thirty-one women with a diagnosis of stress urinary incontinence with intrinsic sphincteric deficiency underwent one periurethral collagen implant between January and December 1994. Three months after the procedure ultrasound evaluation was performed using a 5 MHz probe placed at the vaginal introitus. Subjective assessment and cough stress test were used to measure outcomes. Twenty-five women were available for evaluation 1 year after the procedure. A successful outcome was found in 18 of the 25 women subjectively (72%) and in 16 objectively (64%). A distance of the collagen from the bladder neck of less than 7 mm was found to be associated with a positive outcome. This threshold was found to have a sensitivity of 83.3%, specificity of 85.7%, a positive predictive value of 93.7% and a negative predictive value of 66.6%.

Collagen↗

PubMed1996

Transvaginal bladder neck suspension to Cooper's ligament: a modified Pereyra procedure.

We describe a modified Pereyra procedure with fixation of the bladder neck to Cooper's ligament. The anterolateral attachments of the paraurethral tissue to the inferior pubic ramus are exposed through a vaginal incision. Sutures are placed in the detached endopelvic fascia together with vaginal wall without epithelium and passed suprapubically through small ipsilateral skin and fascial incisions made slightly lateral to and at the level of the pubic symphysis, allowing visualization of Cooper's ligament. The sutures are passed through Cooper's ligament and tied to suspend the bladder neck. All ten women in whom we have done this operation have been subjectively cured of stress incontinence. Five have had long-term urodynamic follow-up. Four of these were dry by objective criteria, after a mean follow-up time of 18 months (range 15-23). The other patient was subjectively dry but had urodynamic evidence of recurrent stress incontinence.

Female↗

PubMed1996

Effects of human atrial natriuretic peptide in patients after coronary artery bypass surgery.

OBJECTIVES: To determine the effects of synthetic human atrial natriuretic peptide (ANP) on renal function, hemodynamics, and levels of vasoactive peptides when infused in the immediate postoperative period after coronary bypass surgery in patients with normal kidney function. DESIGN: A prospective, randomized, double-blind, placebo-controlled study. SETTING: The Department of Cardiothoracic Anaesthetics and Intensive Care of a university hospital. PARTICIPANTS: Thirty patients with normal kidney function scheduled for elective coronary bypass surgery. INTERVENTIONS: During the first 3 hours postoperatively, patients received an infusion of either ANP 7.5 pMol/kg/min (ANP) or vehicle alone (C). MEASUREMENTS AND MAIN RESULTS: No differences were found between the two groups in respect to sex, degree of coronary disease, preoperative medical treatment, or duration of cardiopulmonary bypass and aortic occlusion. Plasma ANP levels increased nearly 10-fold from a mean of 7.0 +/- 1.1 pMol/L in ANP and remained at baseline levels in C, (p < 0.001). In ANP, there occurred significant increases in urine flow (p < 0.001), inulin clearance (p < 0.001), filtration fraction (p = 0.007), and fractional clearance of sodium (p < 0.001) and of osmoles (p < 0.001) compared with C. During the study, no differences in mean arterial pressure, heart rate, and right atrial or pulmonary capillary wedge pressure were detected between the groups. Cardiac index decreased by 5% in ANP compared with a 9% increase in C (p = 0.027). Vasopressin levels significantly increased in C but remained at baseline levels in ANP (p = 0.031). There were no changes in levels of catecholamines or angiotensin II. CONCLUSIONS: The results of this study show that ANP increases diuresis, natriuresis, and glomerular filtration in the immediate postoperative period after coronary bypass surgery.

Aged↗

PubMed1996

Fitness patterns and phenotypic plasticity in a spatially heterogeneous environment.

We analyse patterns of the means and variances of genotypic fitnesses across different niches in a randomly mating haploid population. The population inhabits a spatially heterogeneous environment where it is subject to mutation and weak multilocus additive selection, with different election coefficients in different niches. Approximate analytical expressions are derived for the stationary mean and variance of genotypic fitnesses among the niches in terms of environmental and genetic parameters. As a special case, we analyse an environment described by a variable t, distributed among the niches with mean t(star) and variance D(star) and quadratic decrease in correlation between environments as a function of the difference in values of t. If the niches have the same qualities, the mean and variance of genotypic fitnesses evolve to be quadratic functions of t that achieve their maximum and minimum, respectively, at t(star). With unequal niche qualities, these are non-polynomial functions that attain their extrema at different, usually intermediate values of t, although the coefficient of variation of the genotypic fitnesses still attains its minimum near t(star). The functions involve the total mutation rate, the combination of the loci to genotypic fitnesses, and the frequency and quality distributions of the niches. Thus, for this relatively simple model the norms of reaction may be calculated in terms of the detailed properties of the environmental heterogeneity, and the genetic system.

Biological Evolution↗

PubMed1996

Structural characterization by mass spectrometry of hemoglobin adducts formed after in vivo exposure to methyl bromide.

A mass spectrometric procedure is described for the structural study of the adducts formed in human hemoglobin by in vitro exposure of erythrocytes to the alkylating agent methyl bromide using different protein to reagent ratios. Peptide mapping by HPLC and tandem mass spectrometry allowed location of methylated amino acids within the protein sequence. A prominent reactivity of several nucleophilic side chains in human hemoglobin subunits was observed, which was modulated by the concentration of the alkylating agent. Cysteine residues, the main reactive sites, were fully methylated in hemoglobin exposed to a 10-fold excess of methyl bromide, differently from other residues, including histidines, showing a heterogeneous pattern of methylation that was largely directed by their environment. No evidence of methylation was found at the heme proximal histidines beta92 and alpha87. A more selective methylation was obtained when the ratio methyl bromide: hemoglobin was lowered to about 1:1. In this last case only specific residues were reactive. Among them, the N-terminal amino group of both alpha- and beta-globins, cysteine 104 in the alpha-chain and cysteine 93 (not cysteine 112) in the beta-chain, indicating a different accessibility to reaction of the sulfhydryl groups on the protein chain. Thus hemoglobin side chains are selectively modified and the degree of modification at each site is a function of the position of the single amino acid residue within the protein quaternary structure, raising the possibility that alterations of structure and functional properties of human hemoglobin following exposure to alkylating agents may be mediated through such covalent protein modifications. The results obtained demonstrate the usefulness of the analytical approach for the characterization of hemoglobin adducts with methyl bromide or similar compounds, which can constitute the basis for biomonitoring of human exposure.

Alkylation↗

PubMed1996

Methylsulfonyl metabolites of PCBs and DDE in human milk in Sweden, 1972-1992.

A multicomponent method used for analysis of organochlorine pesticides, polychlorinated biphenyls (PCBs), naphthalenes, dibenzo-p-dioxins, and dibenzofurans was adapted for the analysis of methylsulfonyl metabolites of chlorinated biphenyls (MeSO2-CBs) and of p,p'-DDE (MeSO2-DDE) in human milk. The extraction and initial purification was made by liquid-gel partitioning. Additional purification and separation steps were achieved by adsorption and gel permeation chromatography. The mean recoveries of 23 MeSO2-CBs and MeSO2-DDE standards, added to the milk before extraction, were 80-97%. Human milk sampled in Stockholm during 1972, 1976, 1980, 1984/85, 1990, 1991, and 1992 was analyzed by GC-MS. During the time course studied, the concentrations of MeSO2-CBs decreased from approximately 9 to 2 ng/g lipids and of MeSO2-DDE from 5 to 0.4 ng/g lipids. The concentrations of MeSO2-CBs and MeSO2-DDE correlated to the levels of total PCB and p,p'-DDE, respectively. 3-MeSO2-DDE was the major isomer of the aryl methyl sulfones studied in the milk. PCB methyl sulfones with five and six chlorine atoms in the molecule were predominant among the PCB methyl sulfones Generally, the concentrations of 4-MeSO2-CBs were higher than the corresponding 3-MeSO2-CB compound. The major MeSO2-CBs in the milk were 4-MeSO2-2,5,2',3',4'-pentaCB (4-87) and 4-MeSO2-2,3,6,2',4',5'-hexaCB (4-149).

Female↗

PubMed1996

Skin and liver diseases induced in flounder (Platichthys flesus) after long-term exposure to contaminated sediments in large-scale mesocosms.

Disease development in flounder (Platichthys flesus) was studied over a period of 3 years in three large mesocosms (40 m x 40 m x 3 m). Two of the mesocosms contained clean sand and the third, sharing a common water circulation with one of the clean-sand mesocosms, was stocked with contaminated dredged spoil. In this way, one of the clean-sand mesocosms was indirectly polluted via the water phase, and analysis of contaminant concentrations in sediments and flounder tissues showed that it had a status intermediate between the other two. Random samples of the flounder populations from the indirectly polluted and reference mesocosms were examined every 2 months for epidermal diseases (lymphocystis, skin ulcers, fin rot) and then released. In addition, every 6 months, random samples of fish from all three mesocosms were sacrificed for histological and chemical investigation. With regard to the development of epidermal disease, the results showed little difference between the reference mesocosm and the indirectly polluted mesocosm, with the exception that lymphocystis was significantly elevated in the indirectly polluted mesocosm. Although pollution may be a risk factor in the etiology of this disease, such a relationship would probably be obscured under field conditions due to variation arising from other factors. Histopathological analysis of the livers revealed in total four cases of hepatocellular adenoma (1.5% of sampled population) in fish from the polluted mesocosms, the first occurring after 2.5 years of exposure in fish from the indirectly polluted mesocosm. Furthermore, several other liver lesions, including foci of cellular alteration and hydropic vacuolated lesions, developed during the course of the experiment before tumor formation was apparent. Prevalences of these conditions were very much lower in the reference mesocosm than in the two polluted mesocosms. Densities of melanomacrophage centers in the liver showed a similar trend. The findings clearly indicate that long-term exposure to chemically contaminated dredged spoil can induce liver neoplasia and other liver lesions in flounder at contaminant levels comparable to those found in the natural environment.

Animals↗

PubMed1996

Two women and their mothers: on the internalization and development of mother-daughter relationships.

This is a report from a 30-year followup study conducted by a member of Margaret Mahler's original separation-individuation research team. Based on a series of unstructured, clinical interviews with the original subjects and psychological testing of the subjects and their mothers, two mother-daughter pairs are compared from the perspective of the meaning of each daughter to her mother, how that meaning influenced the separation-individuation process, and how it influenced the unfolding of each daughter's life as a woman. Because the mother-child pairs were observed several times a week by both participant and nonparticipant observers beginning during the preverbal period, this study offers a unique opportunity to examine the influence of the earliest interactions on adult life.

Adolescent↗

PubMed1995

An integrated analytical method for determination of polychlorinated aryl methyl sulfone metabolites and polychlorinated hydrocarbon contaminants in biological matrices.

A simple column chromatography method was developed for separation and cleanup in the determination of chlorinated hydrocarbon contaminants and their methyl sulfone (MeSO2-) metabolites in biological tissues. The method was validated for determination of 11 polychlorinated biphenyls (PCBs), 15 tetra- to heptachloro 3- and 4-MeSO2-PCBs, 3-MeSO2-DDE, and tris(4-chlorophenyl)-methanol spiked to herring gull egg, smelt, and polar bear liver and adipose tissue using gas chromatography with electron-capture detection (GC-ECD). The overall mean recovery relative to the internal standard was 103% +/- 8%, independent of analyte, substrate type, and lipid extract weights up to approximately 0.7 g. Precision of replicate analyses of individual congeners was good. There were no significant residual biogenic or xenobiotic interferences in the aryl methyl sulfone fraction of any substrate. Sensitivity and linearity of molar response of MeSO2-PCBs and MeSO2-DDE was tested for ECD and electron-capture negative ion mass spectrometry monitoring the total ion current (TIC) and the molecular ion (SIM). The mean practical quantitation limit among MeSO2-PCBs and 3-MeSO2-DDE was lowest for SIM (2.1 +/- 0.9 pg) and similar for ECD and TIC (24.2 +/- 4.6 and 44.4 +/- 17.1 pg, respectively). Response factors were linear above the practical quantitation limit to at least the nanogram level for all three techniques. In spite of superior sensitivity, there was more inherent variability in the response factors for SIM (approximately 18%-56% CV) than for ECD (approximately 7%-12% CV) or TIC (approximately 11%-18% CV); therefore, ECD or TIC is recommended for quantitative analysis.

Animals↗

PubMed1995

Distractibility in schizophrenia.

This study examined the effects of neuroleptic medication on the allocation of attentional resources to distracting stimuli in patients with schizophrenia. Twenty-five patients were tested twice (medication-free and after medication stabilization) on the Identical Pairs versions of the Continuous Performance Test under both distraction and no-distraction conditions. Sixteen patients were chronically ill adults and nine patients were young neuroleptic-native patients in the early stages of illness. Results indicated that neuroleptic treatment did not improve distractibility for either group and that both groups were comparably distractible. These findings suggest that medication does not improve the misallocation of attention to distracting stimuli in patients with schizophrenia.

Acute Disease↗

PubMed1995

Geographical distribution and identification of methyl sulphone PCB and DDE metabolites in pooled polar bear (Ursus maritimus) adipose tissue from western hemisphere arctic and subarctic regions.

The geographical distribution of methyl sulphone (MeSO2-) PCB and DDE metabolites is unknown for any species in any region. In this study, pooled male polar bear (Ursus maritimus) adipose samples from 12 arctic and subarctic regions from the Bering Sea to the Greenland Sea were analyzed for PCBs, DDE, and their MeSO2-metabolites. Each adipose pool contained from three to 27 lipid extracts prepared on an equal fat basis. The total (S-) MeSO2-PCB and MeSO2-DDE levels were generally higher in the east (Greenland) and south (Hudson Bay) and ranged from 138 to 633 ng/g lipid and 0.8-11 ng/g lipid, respectively. Five new MeSO2- compounds were identified and/or quantitated, 3M-DDE, 4M-CB64, 3M- and 4M-CB70, and 3M-CB149. The congeners 3M- and 4M-CB101 and 3M- and 4M-CB87 consistently accounted for ca. 50% of the S-MeSO2-PCBs. The MeSO2-PBC congener pattern was independent of geographic variation among the regions, implying that the pattern of atmospheric input and subsequent biomagnification of precursor PCBs is homogeneous in the western hemisphere. The ratio of S-MeSO2-PCBs to accumulating PCBs decreased very gradually (average value of .056 +/- .012) from west to east reflecting the proportion of higher chlorinated PCBs that are not major precursors of MeSO2-PCBs. The 3-MeSO2-DDE/DDE ratio fluctuated among regions with an average value of .033 +/- 0.017 [corrected].

Adipose Tissue↗