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Biomedical subjects

A Bergman

Publications and source records attributed to A Bergman.

At least 127 records · Page 7Linked to original sources
PubMed1993

Liver accumulation of 2,3,7,8-tetrachloro-[3H]dibenzofuran in mice: modulation by treatments with polychlorinated biphenyls.

The distribution of 2,3,7,8-tetrachloro-[3H]dibenzofuran ([3H]TCDF; 40 micrograms/kg) resembled that earlier reported for 2,3,7,8-tetrachlorodibenzo-p-dioxin, with a strong accumulation in the liver and a selective uptake in the nasal olfactory mucosa of adult and fetal mice. Pretreatments with a series of selected congeners of polychlorinated biphenyls (PCBs), i.e.. I (IUPAC)-77, I-105, I-118, I-126, I-153, I-156, I-169, and a commercial preparation, Aroclor 1254 (25-100 mg/kg body wt. i.p.), were found to modulate the hepatic uptake of [3H]TCDF (24 h post-3H-injection). At a short pretreatment time (4 h), non-ortho-chlorinated congeners decreased the uptake of [3H]TCDF equivalents in the liver (e.g., I-126 = 3,3',4,4',5-pentachlorobiphenyl: 34% of control), while several mono- and di-ortho PCB congeners and Aroclor 1254 increased the hepatic uptake of [3H]TCDF (e.g., I-156 = 2,3,3',4,4',5-hexachlorobiphenyl: 183% of control). At a longer pretreatment time (48 h), both a non-ortho (I-169 = 3,3',4,4',5,5'-hexachlorobiphenyl) and mono-ortho PCB congener(s) (e.g. I-156) markedly increased the hepatic 3H-uptake (190%), a probable effect of an induction of hepatic binding sites for TCDF. Ethoxyresorufin-O-deethylase activities, regarded to mirror the metabolic activity of cytochrome P-450 IA1 (CYP IA1), were strongly and time-dependently induced after I-169, but not after I-156, pretreatment (25 mg/kg). The initial liver concentrations of the two PCB congeners were similar and increased for I-169 but not for I-156 at later time points. In conclusion, the results show a selective uptake of [3H]TCDF in the mouse liver and nasal olfactory mucosa of both dam and fetus. The uptake of [3H]TCDF in the liver is influenced both by dose and pre-exposure with PCBs. The presence of a PCB-sensitive, but CYP IA1-independent, hepatic binding site for TCDF is suggested. Consequently, pharmacokinetic interactions with PCBs complicate the toxicity assessment of TCDF in complex mixtures.

Animals↗
PubMed1993

Biodegradation of 4-nonylphenol in seawater and sediment.

Biodegradation of 14C-labelled nonylphenol at the concentration 11 microg litre (-1) in seawater has been estimated by collection and quantification of the formed labelled carbon dioxide. Initially degradation was very slow but when the microorganisms had become adapted, after four weeks at 11 degrees C, the degradation rate increased rapidly and after 58 days about 50% of 14C from NP was found in the CO2 fraction. In the presence of sediment the initial degradation rate was high and did not increase after longer incubation. Lack of oxygen reduced the degradation rate by half in the presence of sediment.

Journal Article↗
PubMed1993

Detecting fatty acids of dietary origin in normal and cancerous human breast tissue by 13C nuclear magnetic resonance spectroscopy.

Natural abundance 13C NMR was used to determine relative amounts of fatty acid subclasses present in fibroadipose tissue from the human breast in healthy and cancer patients and in breast carcinoma tissue. Resonances corresponding to the carbon atoms of triacylglycerides were obtained when adipose tissue constituted more than 10% of the carcinoma. Resonances corresponding to phospholipids and proteins were also observed when the percentage of adipose tissue was lower. No significant difference between the levels of unsaturated fatty acids in adipose tissue from cancer and non-cancer patients was found. However, significant differences in the levels of monounsaturated and saturated fatty acids of carcinoma compared to non-cancerous tissue was found, as was a nearly significant difference for the levels of polyunsaturated fatty acids in these two tissue types. These findings suggest an alteration of cellular lipid composition in neoplastic mammary tissue.

Breast↗
PubMed1993

Estrogen effects on the urethra: beneficial effects in women with genuine stress incontinence.

The urethra, which originates from the urogenital sinus, is under the influence of estrogen just like the vagina. The concentration of estrogen receptors in the urethral mucosa is similar to that of the vaginal mucosa. Estrogen deprivation will result in atrophic urethritis and sometimes urinary incontinence, and estrogen replacement therapy may reverse this trend. Estrogens have been shown to increase urethral pressure in up to 30 per cent of women and to significantly improve or cure stress urinary incontinence in many cases. Adding alpha-sympathomimetic drugs to estrogens may further improve symptoms in women with stress incontinence. It seems that vaginal estrogens have more beneficial effect on the urethra, compared with the oral medication, although prospective control studies have not always supported these findings. Overall, it seems that estrogens have beneficial effects on urethral function in women with postmenopausal stress incontinence, although more prospective randomized control studies are needed to assess the effect of estrogens on the lower urinary tract.

Estrogen Replacement Therapy↗
PubMed1993

Prostaglandin prophylaxis and bladder function after vaginal hysterectomy: a prospective randomised study.

OBJECTIVE: To assess the efficacy of prostaglandins in enhancing bladder function after vaginal hysterectomy. DESIGN: Prospective randomised study of women who underwent vaginal hysterectomy between November 1989 and August 1990. SETTING: Sackler School of Medicine Tel Aviv University Medical Center, Department of Obstetrics and Gynaecology 'B'. SUBJECTS: 24 women who underwent vaginal hysterectomy and anterior and posterior colporrhaphy for prolapse. INTERVENTION: Administration of prostaglandin F2 alpha 5 mg intravesically or E2 3 mg intravaginally versus 100 ml saline intravesically (control) daily, starting on the first postoperative day, until adequate spontaneous voiding was established. RESULTS: Women receiving PGE2 resumed spontaneous bladder functions earlier, required significantly fewer days catheterisation and had significantly less febrile morbidity compared to women in the control group or PGE2 group. CONCLUSIONS: Prostaglandins PGE2 intravaginally are beneficial in enhancing functions after vaginal hysterectomy [corrected].

Adult↗
PubMed1993

[PCB methylsulfone accumulated in muscle of mink dosed with PCB (Clophen A50)].

The structural requirements of the parent PCBs for the formation of the retained PCB methylsulfones (MeSO2-CBs) were investigated in mink (Mustela vison) exposed to PCB (Clophen A50). Muscle was analyzed for the MeSO2-CBs, which were determined by comparison of synthesized reference compounds. Major unmetabolized CBs such as 2, 4, 5, 2', 4'-pentaCB, 2, 4, 5, 2', 3', 4'-hexaCB, 2, 4, 5, 2', 4', 5'-hexaCB and 2, 3, 4, 5, 2', 4', 5'-heptaCB were determined in high concentrations in the mink muscle. All these PCBs are substituted in the 2, 4, 5-positions of at least one of the phenyl rings. On the other hand, CBs with free meta/para-positions were readily metabolized. Thus, at least 25 MeSO2-CBs were detected at concentration of 16 micrograms/g in extracted lipids from the muscle, corresponding to one tenth of PCB levels. Most of the methyl sulfone metabolites were 3- and 4-MeSO2-CB isomers of PCBs known to be rapidly metabolized, e.g. 2, 4, 2', 5'-tetraCB, 2, 3, 6, 4'-tetraCB, 2, 5, 3', 5'-pentaCB, 2, 4, 5, 2', 5'-pentaCB, 2, 3, 4, 2', 5'-pentaCB, 2, 3, 6, 3', 4'-pentaCB, 2, 3, 6, 2', 4', 5'-hexaCB and 2, 3, 6, 2', 3', 4'-hexaCB. 3-MeSO2-2, 5, 2', 5'-tetraCB and 3-MeSO2-2, 5, 6, 2', 5'-pentaCB were also found to be retained in the muscle, but their isomeric 4-MeSO2-CBs were not detected. Both the 3- and 4-MeSO2-2, 5, 6, 2', 4', 5'-hexaCB isomers were identified in the muscle extracts while no MeSO2-CB metabolite originating from 2, 3, 2', 4', 5'-pentaCB were detected in the muscle. These results show the PCBs with at least one phenyl ring with 2, 5-dichloro- and 2, 3, 6-trichloro-substitution are strongly favored and may be considered a criterion for the formation of MeSO2-CBs accumulated in mink muscle. These observations are in accordance with MeSO2-CBs detected also in other mammals.

Animals↗
PubMed1993

[Accumulation of hydroxylated PCB metabolites in blood].

In order to investigate some potential accumulate properties of hydroxylated PCB metabolites, blood and tissues such as livers, kidneys, lungs and adipose tissue from rats exposed to a commercial PCB (Aroclor 1254) were analyzed for hydroxylated PCBs (OH-PCBs). A large number of OH-PCBs were detected in the liver 1 day after exposure among which almost 13 have been identified in the blood. OH-PCBs were retained selectively in the blood probably due to binding between the OH-PCBs and a protein in serum. One major OH-PCB determined in rat blood was 4-OH-2', 3, 3', 4', 5-pentaCB formed from 2, 3, 3', 4, 4'-pentaCB after NIH shift. Blood of a grey seal from the Baltic also contained at least 8 OH-PCB congeners with 2 major compounds determined as 4-OH-2', 3, 3', 4', 5-pentaCB and 4-OH-2, 3, 3', 4', 5, 5'-hexaCB. Thus, 4-OH-2', 3, 3', 4', 5-pentaCB is the most retainable OH-PCB congener in blood from rats and seal. Human serum have also been found to contain a few number of OH-PCBs at concentration of 0.6 ng/g serum which corresponds to one fourth of PCB level.

Animals↗
PubMed1993

Pelvic muscle exercises: when do they work?

OBJECTIVE: To identify urodynamic indices that can predict the outcome of pelvic muscle exercises in women with genuine stress urinary incontinence. METHODS: Thirty-six women with genuine stress urinary incontinence were evaluated during a 6-month period. Urodynamic studies were performed before and 3 months after completion of a program of Kegel pelvic muscle exercises. Subjective symptoms and objective loss of urine as well as pad count were used to evaluate the outcome of the exercise program. A receiver-operating characteristic curve was used to assess the prognostic value of the pressure transmission ratio between the abdomen and urethra. RESULTS: Twenty patients (56%) were cured or substantially improved 3 months after completing the pelvic muscle training, whereas 16 were unchanged. The urethral closure pressure significantly increased in the subjects cured or improved. After successful training, significant changes were noted in the pressure transmission ratio between the abdomen and urethra on cough. Six of seven subjects with mild incontinence responded favorably, whereas 13 of 15 with severe incontinence did not improve after the training. The pressure transmission ratio plotted on a receiver-operating characteristic curve was found to have optimal predictive value at the 80% level. CONCLUSION: Kegel pelvic muscle exercises give a better outcome in women with mild stress urinary incontinence and/or with a pressure transmission ratio between the abdomen and urethra of 80% or more.

Exercise Therapy↗
PubMed1993

High-risk indicators for family involvement in social work in health care: a review of the literature.

Shifts in health concerns, fiscal restraints, technological advances, and demands for accountability have created severe tensions within health care settings. New demands point to the need for a redefinition of services. High-risk screening appears to be a clear method of delineating service need. A review of the empirical literature highlights individual, family, and illness variables that alone and together may improve identification of patients and families in need of social work services. The development of screening mechanisms may be a useful vehicle for improved psychosocial care and for the planning of social work services.

Canada↗
PubMed1992

Antibiotic prophylaxis following lower urinary tract instrumentation.

The value of routine antibiotic prophylaxis was assessed in 362 women undergoing lower urinary tract instrumentation. A three-day course of a once-a-day dose of 1 g of cefadroxil was compared with a three-day course of 100 mg of nitrofurantoin three times a day, in a randomized investigator blinded placebo controlled study. Both study drugs were significantly more effective in preventing postinstrumentation urinary tract infections than placebo (p less than 0.003). Differences in efficacy between the two test drugs were not significant; however, side effects in the nitrofurantoin group were more frequent and severe than those in the cefadroxil group. Cefadroxil also offered the advantage of a once-daily dosing schedule.

Adult↗
PubMed1992

Adrenocortical toxicity of 3-methylsulphonyl-DDE; 3: Studies in fetal and suckling mice.

Irreversible binding and toxicity of the DDT metabolite 3-methylsulphonyl-DDE (MeSO2-DDE) were examined in fetuses and suckling pups following administration to pregnant or lactating C57Bl mice. Tape-section autoradiography showed a high and tissue-specific accumulation and binding of MeSO2-DDE-14C-derived radioactivity in the late gestational fetal adrenal cortex. According to microautoradiography an irreversibly bound residue was confined to the zona fasciculata. Similarly, there was a high concentration of irreversibly bound 14C-labelled material in the adrenal zona fasciculata of suckling pups. Intraperitoneal injection of MeSO2-DDE-14C to lactating mice resulted in higher concentrations of radioactivity in the liver and stomach contents (milk) of the suckling pups than in the maternal liver. This treatment also resulted in a higher level of radioactivity in the adrenals of the pups than in the maternal adrenals, both at a subtoxic and at a toxic dose. Histopathologic examination of adrenals from suckling pups revealed extensive vacuolation and necrosis of the zona fasciculata 2 days following a single dose of MeSO2-DDE (25 mg/kg) to the dam. In the fetal adrenal zona fasciculata, slight degenerative changes were observed following a maternal dose of 50 mg/kg. In conclusion, the study shows that MeSO2-DDE is a highly tissue-specific toxicant to the fetal and postnatal adrenal zona fasciculata in mice. Based on the present data and on previous results in adult mice, we propose that a tissue-specific activation to a reactive metabolite in the fetal and postnatal adrenal cortex is mediated by cytochrome P-450 (11 beta).

Adrenal Cortex↗
PubMed1992

Advancing social work practice in the health field: a collaborative research partnership.

This article describes and analyzes the development of a collaborative research model by one university faculty of social work and 10 health care settings. Established working relationships for educating students were the foundation of a research partnership formed to study questions of mutual interest. This article discusses the developmental stage of the research consortium, including needs assessment, workshop, identification of a common theme and research topic, preliminary funding, and literature review. This stage resulted in the decision to develop and test an instrument to screen for high social risk that would be capable of identifying the need for social work involvement with families to provide effective and efficient management of patients. The Delphi methodology was chosen in the first phase of the research design, and reasons for the choice of this methodology, the results from the two Delphi rounds, and a preliminary screening instrument are presented. Finally, issues in collaboration, such as institutional factors, dynamics of the working group, and leadership roles, are analyzed to identify facilitating features and problematic issues in such partnerships.

Academies and Institutes↗
PubMed1992

The modified Pereyra procedure: a clinical and urodynamic review.

OBJECTIVE: To review the clinical and urodynamic outcome of treatment by the modified Pereyra procedure in 93 women with genuine stress incontinence. DESIGN: Retrospective review. SETTING: Harbor/UCLA Medical Center and Los Angeles County Women's Hospital, Los Angeles, California, USA. MAIN OUTCOME MEASURES: Clinical and urodynamic assessment one year after modified Pereyra procedure. RESULTS: Overall 82% of patients were subjectively cured while only 63% were objectively cured. Women with failed surgery had significantly lower pre-operative maximum urethral closure pressures. The procedure had a low operative and postoperative morbidity with no significant disturbance of voiding function noted at one year follow-up. CONCLUSIONS: Our results with the modified Pereyra procedure for stress incontinence showed a significantly lower success rate than has been reported from many previous studies.

Adult↗
PubMed1992

Enrichment of metabolites in the cerebrospinal fluid of cod (Gadus morhua) following oral administration of hexachlorobenzene and 2,4',5-trichlorobiphenyl.

The disposition of 14C-labelled hexachlorobenzene (HCB) and 2,4',5-trichlorobiphenyl (triCB) was studied in cod (Gadus morhua) and rainbow trout (Oncorhynchus mykiss). For both compounds tape section autoradiography revealed substantial amounts of radiolabelled material in the central nervous system (CNS) of cod, whereas only traces of radioactivity were observed in the CNS of rainbow trout. Furthermore, an enrichment of radiolabelled compound in the cerebrospinal fluid (CSF) was observed in the cod, whereas no radioactivity could be detected in the CSF of rainbow trout. According to autoradiography, the CNS of cod dosed with HCB contained the parent compound, whereas the major part of radioactivity in CSF was due to HCB metabolites. Thin-layer chromatography of extracts from cod dosed with triCB showed the presence of parent compound in the CNS, whereas part of the radioactivity in the CSF was due to triCB metabolites. The activities of cytochrome P-450 and UDP-glucuronosyltransferase in the CNS of cod and rainbow trout were determined in microsomal and mitochondrial fractions. Both species expressed activities which were in the same order of magnitude as those reported for the corresponding fractions from rat brain. Incubation of triCB with cod brain mitochondria and microsomes resulted in the formation of two polar metabolites. It is suggested that cod may be more vulnerable than rainbow trout regarding neurotoxicological effects of HCB, triCB and related environmental pollutants.

Administration, Oral↗
PubMed1992

Metabolism of 1,2,4-trichlorobenzene in rats: examination of thiol formation.

1. More than 60% of oral doses of 14C-1,2,4-trichlorobenzene (ca. 21 mg/kg) administered to rats were excreted in bile as S-trichlorophenyl-mercapturic acid pathway metabolites. 2. The biliary metabolites were ultimately excreted in urine mainly as the isomeric mercapturic acids. 3. An acetylated glutathione conjugate was isolated as a major metabolite in bile (8% dose). The acetyl group was shown by mass spectrometry to be on the glutamyl moiety. 4. A glutamylcysteine conjugate of trichlorobenzene was also isolated from bile as a major metabolite (8% dose). 5. Trichlorothiophenols were deduced not to be intermediates or end-products of enzymic metabolism of trichlorobenzene in rats because 14C-2,4,5-trichlorothiophenol dosed i.p. to rats was excreted as the S-glucuronide (17% dose) and as S-(methylsulphonyl-dichlorophenyl)-mercapturic acid (36% dose).

Acetylcysteine↗
PubMed1992

Anatomic and functional assessment of stenosis severity with intravascular ultrasound imaging in vitro.

An in vitro study was performed to evaluate the accuracy of intravascular ultrasound imaging compared with roentgenography for determining the cross-sectional area of a lumen; and to determine if the functional significance of an irregular stenosis is predicted more accurately by intravascular ultrasound than roentgenography. Varying degrees of stenosis were made in 17 rubber tubings by adjusting a plastic constrictor. The cross-sectional areas at the normal and the stenotic segments were determined by intravascular ultrasound, roentgenography, and then measured directly from an acrylamide gel cast of the lumen. To evaluate the functional significance of a stenosis, the pressure drop across the stenosis was measured using a fluid pumping circuit. The actual pressure drop was then compared with the predicted pressure drop derived from hydrodynamic equations using cross-sectional areas obtained by intravascular ultrasound or roentgenography. There was an excellent correlation between the cross-sectional areas at the tightest stenosis measured by intravascular ultrasound compared with the area from the acrylamide cast (7.2 +/- 2.6 v 6.6 +/- 2.4 mm 2, mean +/- SD, r = .93). Measurements of cross-sectional area from the roentgenograms (10.9 +/- 3.9 mm 2) also provided a relatively good correlation with those from the acrylamide casts (r = .84); however, the roentgenograms consistently overestimated the cross-sectional area of the stenosis. The mean values of the actual pressure drop and the predicted pressure drop by intravascular ultrasound and roentgenograms were 15.7 +/- 13.5, 11.3 +/- 11.9, and 4.3 +/- 4.5 mmHg, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗