Search PubMed⌕ Search

Biomedical subjects

I Meyer

Publications and source records attributed to I Meyer.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Age related decrease of high density lipoproteins (HDL) in women after menopause. Quantification of HDL with genetically determined HDL arylesterase in women with healthy coronary vessels and in women with angiographically verified coronary heart disease].

BACKGROUND: The decline in the concentration of high density lipoproteins (HDL) observed in postmenopausal women is thought to contribute to the increasing incidence of coronary artery disease (CAD) after menopause. Human serum arylesterase (EC 3.1.1.2) is exclusively associated with HDL. We therefore investigated possible differences in the decline of HDL-levels and of HDL-subfractions HDL2 and HDL3 between postmenopausal women without and with angiographically documented CAD. PATIENTS AND METHODS: HDL-, HDL2-and-HDL3- concentrations were studied in postmenopausal women with angiographically documented CAD (n = 24; 51 to 72 years mean: 62 years) and compared to HDL-parameters of women without CAD (n = 22; 51 to 81 years, mean: 58 years). Arylesterase activities of HDL2-and HDL3-subfractions and HDL2-cholesterol concentrations were determined after differential precipitation with polyethylene glycol (4.7 mM PEG). Phenotyping of HDL-arylesterase was achieved in CAD patients and in women without CAD after determining hydrolysis of arylesterase substrates paraoxon (PO) and phenylacetate (PA) by calculating paraoxonase/arylesterase activity ratios R (R = [PO]/[PA] x 1000): phenotype A (n = 26) with R < 2.5, phenotype AB (n = 16) with 5.0 < R < 10.7, and phenotype B (n = 4) with R > 13.5. RESULTS: In postmenopausal women with documented CAD, as compared to women without CAD, HDL-cholesterol (55 +/- 3 mg/dl vs. 69 +/- 3 mg/dl HDL2-arylesterase (25 +/- 1 kU/l vs. 33 +/- 2 kU/l), and HDL3-arylesterase (89 +/- 4 kU/l vs. 106 +/- 5 kU/I) were found to be significantly reduced. Analysis of the correlation of lipid parameters and age revealed in CAD patients, but not in postmenopausal women without CAD, a significant increase of total cholesterol (r = 0.42), and significant reductions of both HDL2-arylesterase (r = -0.47) and HDL3-arylesterase (r = 0.74) with increasing age. In contrast, HDL-cholesterol (r = -0.14) and HDL2-cholesterol (r = -0.06) of CAD patients showed only slight and non-significant reductions with age. Since HDL3-arylesterase was found to be age-dependently reduced in women without CAD (r = 0.17), HDL2-arylesterase of postmenopausal women, among all lipid parameters showed the most pronounced differences between women without CAD and CAD patients. The age-dependent decrease of HDL2-arylesterase in postmenopausal women with CAD does not result from an increased frequency of B-allele carriers in the subgroup of CAD patients with an age above the median (64 years). CONCLUSION: Genetically determined serum HDL-arylesterase is well suited to quantify HDL in postmenopausal women without and with CAD. HDL2-arylesterase of postmenopausal women should be evaluated as a screening parameter for both primary and secondary CAD prevention.

Aged↗
PubMed1998

The effect of lead in tap water on blood lead in children in a smelter town.

Hettstedt, a city in eastern Germany with a long history of mining and smelting of non-ferrous ores, has multiple lead waste deposits and the remains of a former lead smelter and a copper-silver smelter. As part of a cross-sectional study, an analysis of lead concentrations in drinking water and in blood was undertaken to determine the impact of lead in drinking water on the internal burden of lead in children. The geometric mean of blood lead levels among children 5-14 years old was 35.0 micrograms/l with a 95% confidence interval (C.I.) of 33.4-36.7. The geometric mean of lead in the random tap water samples was 0.5 microgram/l (95% C.I., 0.5-0.6) and 0.7 microgram/l (95% C.I., 0.6-0.8) in the stagnant tap water samples. Blood lead levels were somewhat correlated with the random water measures but not the stagnant water measures (random sample: r = 0.12, P = 0.012; stagnant sample: r = 0.04, P = 0.396). After adjustment for relevant confounders, lead in drinking water (random sample) was not significantly associated with blood lead levels. Factors that were significantly associated with blood lead included gender, the city area of residence, lead in house dust, regular contact with dogs and dirtiness of the child after playing outdoors. Based on this study, lead in domestic tap water contributed little to the lead exposure of children in the lead contaminated region of Hettstedt.

Adolescent↗
PubMed1998

A physiologically based kidney model for the renal clearance of ranitidine and the interaction with cimetidine and probenecid in the dog.

Ranitidine renal clearance was investigated in the beagle dog with or without concomitant infusion of cimetidine or probenecid. Ranitidine was excreted mainly by renal tubular secretion. Plasma clearance was reduced by probenecid from 198 +/- 47 to 119 +/- 41 mL min-1 (mean +/- SD.); renal clearance was reduced from 104 +/- 33 to 54 +/- 24 mL min-1 (p < 0.02) by probenecid and to 89 +/- 37 mL min-1 (NS) by cimetidine. Plasma and urine data were analysed simultaneously with a physiologically based kidney model and were both described adequately by the model, although tubular secretion could not be fully characterized as no saturation was achieved despite high dosages. Tubular secretion of ranitidine was simplified to first-order brush-border and basolateral transport across the proximal tubular cell. Basolateral transport was reduced (from 18.4 +/- 7.8 to 13.6 +/- 10.3 min-1 by cimetidine and 3.9 +/- 3.1 min-1 by probenecid), whereas no effect on brush-border exit was found. Estimated inhibition constants of cimetidine and probenecid were 62 and 4 micrograms mL-1, respectively. Summarizing, ranitidine renal pharmacokinetics were accurately described by the physiologically based kidney model presented in this paper. Model calculations suggest that interaction with cimetidine and probenecid results from competition for basolateral ranitidine uptake into tubular cells.

Animals↗
PubMed1997

[Qualitative and quantitative kidney function testing in dogs using MAG3 clearance].

In the presented study 99mTc-MAG3 clearance measurements were undertaken in 14 dogs during renal scintigraphic examination. Of these dogs, 10 showed no renal impairment, the other 4 exhibited clinically manifested nephropathy. It was the aim of these examinations to determine if this type of clearance measurement that is routinely used in human medicine is suitable for diagnosis of canine nephropathy. An algorithm for the calculation of the MAG3-Clearance developed for humans was modified. The clearance measurement can be performed during the renal scintigraphic procedure without any difficulties. In the group of dogs with no renal impairment the clearance values ranged between 6.4 and 8.0 ml/min/kg, whereas in the group of patients exhibiting nephropathies the values ranged between 2.0 and 2.7 ml/min/kg. The suitability of the method for its use in dogs needs to be confirmed with higher patient numbers. In addition, further studies are necessary to precisely assess the correlation between measured clearance values and effective renal plasma flow in dogs.

Animals↗
PubMed1996

-Value of activated blood coagulation time in monitoring anticoagulation during coronary angioplasty-.

Accurate heparin anticoagulation assessment is important to prevent complications (hemorrhage, thrombotic coronary occlusion) during and after coronary angioplasty (PTCA). Paired ACT-, aPTT- and prothrombin time (PT) measurements have not been studied after PTCA using a high dose heparin management. For that reason we analyzed in 150 consecutive patients (115 m., 35 f., 61 +/- 10 y.) immediately after PTCA and at the time of arterial sheath removal aPTT-(Neothromtin, Behring), PT- (Thromborel S, Behring) and ACT-(HR-ACT, HemoTec) values after application of 20,000 U of heparin (5,000 U intravenous, 15,000 U intracoronary) followed by a heparin-infusion (15,000-25,000 U/24 h). Immediately after PTCA in all patients a aPTT above the upper limit of >180 s was found. The average postprocedural ACT was 330 +/- 82 s. Only 9 patients showed an ACT below 200 s. All coronary reocclusions (n = 3) immediately after PTCA occurred in this group. Arterial sheaths were removed 13 +/- 3 h after PTCA. The incidence of minor peripheral bleeding complications at that time was 21% and was related to the anticoagulation level. Major bleeding complications requiring transfusion were noted in only one case. Our findings suggest that after high dose heparinization for PTCA the ACT test provides a reliable and broad range for the assessment of heparin anticoagulation. In contrast to the aPTT the ACT is ideally suited to determine the dosage of heparin infusion and the time of arterial sheath removal after PTCA. ACT measurements are superior to aPTT measurements in heparin anticoagulation assessment during and direct after PTCA.

Aged↗
PubMed1996

[Kidney scintigraphy in dogs and cats using 99mTc-MAG3].

Renal scanning is one of the imaging techniques used to investigate the upper urinary tract. In the present examination, the principles of performing renal scanning in the dog and car are described. Eleven animals with healthy kidneys (six dogs and five cats) were included in the study for the determination of normal scintigraphic findings as well as eight animals (seven dogs and one cat) with renal damage. The following nephropathies were investigated scintigraphically: nephrolithiasis, hydronephrosis, polycystic renal degeneration, renal aplasia, renal hypoplasia, obstruction of the ureter and renal trauma. Renal scanning proved to be easy to perform with acceptable effort in the dog and cat. It allows the simultaneous assessment of renal function on both sides during the phases of renal perfusion and tubular se- and excretion and represents a valuable adjunct to the morphologically orientated radio- and sonography. The nephrogram curves are comparable to those found in man, although the time until reaching the maximum of the curves and elimination half times are shorter. Also, the sequential scintigrams can be divided into the corresponding phases as in man. Through permanent technical development, today there are gamma processors at disposal that allow a faster, comprehensive and sophisticated evaluation. In the present investigation, this was demonstrated by a comparison of two different calculators. However, due to the financial and technical expenditures and the special radiological safety precautions required, renal scanning will be a technique reserved to larger clinics.

Animals↗
PubMed1995

Structural organization of procaryotic and eucaryotic Hsp90. Influence of divalent cations on structure and function.

Hsp90 is a very abundant molecular chaperone that apparently helps to protect cellular proteins from denaturation upon temperature upshift. The unusual ability of Hsp90 to function under conditions where other proteins unfold prompted us to investigate the stability and structural organization of Hsp90 itself. Both procaryotic and eucaryotic members of the Hsp90 family were found to have very similar physicochemical properties: (i) they are stable against thermal unfolding up to at least 50 degrees C, (ii) they show biphasic, reversible unfolding transitions in guanidinium chloride, and (iii) their oligomerization state is strongly and rapidly affected by millimolar concentrations of divalent cations. In the presence of MnCl2 and MgCl2 defined changes in the quaternary structure of Hsp90 could be observed which resulted in a decrease in thermostability and an increased tendency to form larger aggregates. The addition of divalent cations also almost completely abolished the chaperone function of Hsp90 and induced release of folding intermediates of citrate synthase bound to Hsp90. These modulating effects of divalent cations on structure and function of Hsp90 in vitro represent a potential mechanism for regulation of Hsp90 chaperone action in vivo.

Animals↗
PubMed1995

Transient interaction of Hsp90 with early unfolding intermediates of citrate synthase. Implications for heat shock in vivo.

At normal temperatures, Hsp90 is one of the most abundant proteins in the cytosol of various eucaryotic cells. Upon heat shock, the level of Hsp90 is increased even more, suggesting that it is important for helping cells to survive under these conditions. However, studies so far have been almost exclusively concerned with the function of Hsp90 under non-stress conditions, and therefore only little is known about the role of Hsp90 during heat shock. As a model for heat shock in vitro, we have monitored the inactivation and subsequent aggregation of dimeric citrate synthase (CS) at elevated temperatures. Hsp90 effectively "stabilized" CS under conditions where the enzyme is normally inactivated and finally aggregates very rapidly. A kinetic dissection of the unfolding pathway of CS succeeded in revealing two intermediates which form and subsequently undergo irreversible aggregation reactions. Hsp90 apparently interacts transiently with these highly structured early unfolding intermediates. Binding and subsequent release of the intermediates favorably influences the kinetic partitioning between two competing processes, the further unfolding of CS and the productive refolding to the native state. As a consequence, CS is effectively stabilized in the presence of Hsp90. The significance of this interaction is especially evident in the suppression of aggregation, the major end result of thermal unfolding events in vivo and in vitro. These effects, which are ATP-independent, seem to be a general function of members of the Hsp90 family, since yeast and bovine Hsp90 as well as the Hsp90 homologue from Escherichia coli gave similar results. It seems likely that this function also reflects the role of Hsp90 under heat shock conditions in vivo. We therefore propose that members of the Hsp90 family convey thermotolerance by transiently binding to highly structured early unfolding intermediates, thereby preventing their irreversible aggregation and stabilizing the active species.

Animals↗
PubMed1995

HIV prevalence and sexual behavior in a cohort of New York City gay men (aged 18-24).

An ethnically diverse cohort (n = 174) of New York City gay men (aged 18-24) was studied to determine human immunodeficiency virus (HIV) prevalence and to document sexual behavior patterns. Blood tests of 87 men showed an HIV prevalence of 9%, but only 3% of the previously tested men (n = 77) reported knowledge of a positive test result at baseline interview. An annual HIV seroconversion rate of 2% was observed. Ethnic minority men were more likely to test HIV positive. In addition, the median number of both sexual episodes and sex partners, and the proportion of men who engaged in anal intercourse, increased significantly from 1990 to 1991. During this 2-year period, 91% of the men engaged in unprotected receptive oral intercourse, and 37% engaged in unprotected receptive anal intercourse.

Adult↗
PubMed1995

Characteristics of HIV-positive chronically mentally ill inpatients.

The growing population of chronically mentally ill persons who are HIV-positive or who have AIDS has not yet been adequately studied. We describe the entire population of known HIV-positive inpatients in a state psychiatric center in New York City. In this sample, the typical patient with known HIV infection is as likely to be a man as a woman and is a member of an ethnic minority group. HIV-positive patients had multiple risks for HIV infection including injecting drug use (IDU), sex with IDU partners, prostitution and male homosexual activity. Most patients were at a late stage of HIV-infection, typically with CD4+ cell counts of 400. Discharge plans were complicated by HIV illness and most HIV-positive patients had a longer length of hospital stay than non HIV-positive patients. We discuss the need to plan for the management of increasing numbers of HIV-positive patients in inpatient, outpatient, and residential facilities.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Nd:YAG laser excision of a giant gingival pyogenic granuloma of pregnancy.

A 19-year-old Hispanic nullipara experienced the rapid growth of an oral lesion on the right lower gingiva which she had first noticed at 29 weeks gestation. The lesion interfered with oral hygiene and eating. At surgery, the lesion measured 3.5 x 2.5 x 2.0 cm. Biopsy confirmed a pyogenic granuloma ("granuloma gravidarum"). Panorex films showed no bony invasion. The lesion was excised using the Nd:YAG laser under general anesthesia when the patient had reached 36 3/7 weeks gestation. We chose the Nd:YAG laser over the CO2 laser for the removal of this very vascular lesion, because of its superior coagulation characteristics. This technique results in removal of the lesion with less danger of bleeding than with any other surgical technique. The patient did well postoperatively, delivered a healthy 3,884 g infant at 40 6/7 weeks gestation, and has had no recurrence after 15 months of follow-up.

Adult↗
PubMed1993

[Illness and health from a theological-philosophical viewpoint].

The rivalry between priest and physician is more than a curious reminiscence from greco-roman antiquity and the hebrew precursors of christianity (or their medieval aftermath). The guild of physicians has, by its successfully marketed success, outrun the clergy; it fell itself, however, into crisis. A spiritual turn to the roots in prophecy leads theologians to a more realistic self-assessment as defenders of the suffering creature and to new partnership with a novel physician who perceives scientific omnipotence and therefore limits himself to serve the ill.

Bible↗
PubMed1993

HIV seroprevalence among homeless patients admitted to a psychiatric inpatient unit.

OBJECTIVE: This study was conducted to determine the seroprevalence of HIV-1 antibodies among hospitalized homeless mentally ill patients. METHOD: From December 1989 through May 1991 the authors collected discard blood samples from patients consecutively admitted to a psychiatric unit designated for the care of severely mentally ill persons removed from the streets of New York City. The blood samples were tested for HIV-1 antibodies, and the results were analyzed for associations with age, gender, ethnicity, male homosexual activity, and use of injected drugs. RESULTS: The HIV seroprevalence was 6.4% (13 of 203 samples). Patients between ages 18 and 39 accounted for 51.2% of the admissions and 84.6% of the 13 positive results, a seroprevalence of 10.6% for this subsample. Patients under age 40 were more than six times as likely to test positive for HIV antibodies as those 40 or over. Ethnicity did not predict seropositivity. Women were as likely as men to be infected. Although clinicians had noted high-risk behavior on the charts for only three (23.1%) of the 13 positive cases, a recorded history of use of injected drugs was associated with a 6.5-fold greater risk of HIV seropositivity. CONCLUSIONS: One in every 16 patients admitted to the special unit was HIV positive. Age under 40 and use of injected drugs were strongly associated with seropositivity. Because information on high-risk behavior was infrequent, the reasons for younger patients' greater risk are unclear. The homeless mentally ill require outreach efforts to reduce the risk of acquiring or transmitting HIV.

Adolescent↗
PubMed1993

Childhood abuse and neglect among women outpatients with chronic mental illness.

OBJECTIVE: The purposes of the study were to determine the prevalence of childhood sexual abuse, physical abuse, and neglect among women outpatients with severe and persistent mental illness; to examine patterns of co-occurrence of the various types of abuse; and to explore the relationships between childhood abuse and adult psychiatric symptomatology. METHODS: Childhood histories of abuse and data on clinical characteristics of 78 women enrolled in a New York State outpatient clinic were elicited in face-to-face interviews using a structured questionnaire. RESULTS: Sixty-five percent of the women reported histories of some type of abuse or neglect during childhood. Forty-five percent of the sample had been sexually abused, 51 percent had been physically abused, and 22 percent had experienced neglect. Seventy-four percent of the sexually abused women, 70 percent of the physically abused women, and 94 percent of the women who experienced neglect reported at least one additional form of abuse or neglect. Respondents who had been abused in childhood had higher levels of depressive and psychotic symptoms and higher rates of sexual victimization in adulthood than those who had not been abused. Women who experienced neglect as children had higher rates of homelessness in adulthood. CONCLUSIONS: Chronic mentally ill women seem to experience higher rates of abuse and more types of abuse than the general population. Clinicians should try to determine whether chronic mentally ill women have histories of abuse and to develop interventions to meet their special needs.

Adolescent↗
PubMed1993

Sodium polystyrene sulfonate: a cation exchange resin used in treating hyperkalemia.

Sodium polystyrene sulfonate is a cation exchange resin used in the treatment of nonlife-threatening hyperkalemia. Administered orally or rectally, the resin can effectively reduce serum potassium concentrations in the neonate as well as the elderly. Proper administration, assessment of drug effectiveness, and detection and prevention of potential adverse side effects of sodium polystyrene sulfonate are the responsibility of the nephrology nurse.

Cation Exchange Resins↗
PubMed1992

HIV prevention among psychiatric inpatients: a pilot risk reduction study.

An HIV prevention program was piloted on an acute inpatient admission ward. Patients who volunteered to participate had significantly higher rates of histories of substance use than non-participants, suggesting that patients participated based on rational concerns about past HIV risk behavior. The program consisted of 75 minute sessions once a week for seven weeks and was co-led by an HIV counselor and the ward's social worker. Each session focused on a specific topic and included a short presentation of informational material, viewing of an educational videotape, a discussion, and role play and other educational games. In spite of a wide range in functioning among the participants, discussion was lively and participation was good. The pilot program demonstrates that chronic mentally ill patients can engage in, and benefit from, risk reduction programs and that frank and explicit discussion of sexual issues is well tolerated. Recommendations for improvement in the program are discussed.

Acquired Immunodeficiency Syndrome↗