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Biomedical subjects

J Fuchs

Publications and source records attributed to J Fuchs.

At least 145 records · Page 8Linked to original sources
PubMed1993

The 24-hour D/P ratio is a convenient screen for identifying altered peritoneal transport rates.

Peritoneal transport characteristics (PTC) may change without peritonitis, surgery, or other insults. Identifying patients with these changes is essential in adjusting the dialysis prescription to achieve optimal peritoneal dialysis on a long-term basis. Frequent standard peritoneal equilibration tests (PETs) become impractical as the population in individual programs expands. The time demands are burdensome to the nursing staff as well as to the patient. The accuracy of fast PETs is dependent upon the patient's exact adherence to the protocol steps. Utilizing the 24-hour D/P as a marker for altered PTCs has improved the efficiency of our approach to repeating standard PETs and ensuring dialysis adequacy. For adequacy studies, pooled 24-hour dialysate is routinely collected in our unit. The 24-hour D/P ratio correlates well with extrapolations from original PET data and the patient's current dwell times. Discrepancies noted between the patient's actual D/P ratio and the patient's expected D/P ratio alert the clinician to possible PTC changes.

Biological Transport↗
PubMed1993

Studies on lipoate effects on blood redox state in human immunodeficiency virus infected patients.

Several investigators have implicated that human immunodeficiency virus (HIV) infected patients have a compromised antioxidant defense system. Blood antioxidants are decreased and peroxidation products of lipids and proteins are increased in the patients. This may have pathophysiological implications, because antioxidants, such as glutathione, and reactive oxidants are involved in the regulation of the human immunodeficiency virus. Consequently it was suggested that HIV infected patients may benefit from antioxidant supplementation therapy. In a open and unblinded pilot study the short term effect of the natural antioxidant lipoate (Thioctacid) on blood antioxidants and peroxidation products was investigated in HIV positive patients (CDC IV). In the majority of the patients, lipoate increased plasma ascorbate (9 of 10 patients) total glutathione (7 of 7 patients), total plasma thiol groups (8 of 9 patients); T helper lymphocytes and T helper/suppressor cell ratio (6 of 10 patients), while the lipid peroxidation products malondialdehyde (8 of 9 patients) and 4-hydroxynonenal (7 of 9 patients) were decreased. The results of this pilot study indicate that lipoate supplementation changes the blood redox state of HIV infected patients. A prospective and longitudinal therapy study is warranted to investigate the long term effects of lipoate therapy on blood redox state, disease progression and incidence of opportunistic infections in HIV infected patients.

Adult↗
PubMed1993

The effect of estrogen replacement therapy on platelet aggregation and adenosine triphosphate release in postmenopausal women.

OBJECTIVE: To evaluate the effect of hormone replacement therapy on platelet function in postmenopausal women. METHODS: In 51 postmenopausal women, platelet aggregation and adenosine triphosphate (ATP) release were studied before and after estrogen and progestogen treatment and compared with that in untreated patients. An incubation study evaluated platelet function after incubation with estrogen and progestogen. RESULTS: Significant decreases in adrenaline-induced platelet aggregation (P < .01) and ATP release (P < .02) were observed 3 months after initiation of estrogen replacement. Patients receiving replacement regimens consisting of estrogen opposed by progestogen or progestogen alone showed nonsignificant changes in platelet aggregation and release. The most pronounced decrease in platelet function in the incubation assay was detected after incubation with estrogen plus progestogen. Results were similar in the spontaneous- and surgical-menopause patients. CONCLUSION: Estrogen replacement therapy may inhibit the atherosclerotic process by suppressing platelet function.

Adenosine Triphosphate↗
PubMed1992

Circulating aggregated platelets, number of platelets per aggregate, and platelet size during acute myocardial infarction.

Circulating aggregated platelets (total, reversibly and irreversibly aggregated), the number of platelets per aggregate and "big" platelets were measured by a modification of the Wu and Hoak method in 42 patients on the first, second and fifth day of acute myocardial infarction (AMI). Among them, 30 had an uncomplicated course and 12 patients had complications that occurred between the 5th and 10th day of hospitalization (7 patients had reinfarction and 5 died). In all patients the measured parameters were elevated compared with those of control subjects. There was a significant increase, especially after the first observation day, in the values of total aggregated platelets (37 +/- 11% vs 26 +/- 12%, p < 0.001), reversibly aggregated platelets (27 +/- 9% vs 17 +/- 8%, p < 0.001) and the average platelets per aggregate (8.6 +/- 0.3 vs. 2.3 +/- 0.4) in patients with versus without complications. In considering the role of platelets in the development of AMI, these findings may add information to the role of platelets in determining the course of AMI.

Blood Platelets↗
PubMed1992

DNA strand breaks and DNA cross-links in peripheral mononuclear blood cells of ovarian cancer patients during chemotherapy with cyclophosphamide/carboplatin.

DNA strand breaks and DNA cross-links were detected in peripheral mononuclear blood cells of 15 ovarian carcinoma patients by alkaline filter elution. These patients received therapy with 600 mg/m2 of cyclophosphamide and 350 mg/m2 of carboplatin. Blood samples were taken a day before and 16 to 18 h after a therapy cycle. The patients showed an increased elution rate of 37% compared with that of healthy controls before the current cycle of chemotherapy, probably due to treatment in a previous cycle of therapy. The difference was statistically significant (P < 0.02; U test). At the end of the actual cycle of therapy an average acceleration of the elution rate of 157% was found compared with that of controls (P < 0.01; U test). Compared with the rate before the cycle of therapy, the mean elution rate after treatment was accelerated by 89% (P < 0.01; Wilcoxon test). The amount of DNA-protein cross-links was also increased after drug application. The individual patients showed different responses after drug intake. While some patients showed hardly any alteration in the elution rate, others showed an acceleration of up to 400%. Monitoring the course of disease in six of these patients indicated that a strong acceleration in the elution rate after drug application is possibly linked to the success of the chosen cancer treatment as measured by a decrease in the tumor marker CA12-5 to the normal level. In another investigation the group of patients who had received non-alkylating antineoplastic agents showed no increase in DNA strand breaks compared with untreated controls. Thus, monitoring DNA single-strand breaks in the peripheral mononuclear blood cells of patients can help to evaluate the efficiencies of the cancer treatment as a composite of individual differences in resorption, metabolic activation and detoxification, and possibly some constitutional aspects of drug resistance to cyclophosphamide/cisplatin and probably to several other alkylating antineoplastic drugs. This may help in choosing an effective drug and in adjusting the doses of these drugs individually in the chemotherapy of cancer.

Animals↗
PubMed1992

Big platelets in hyperlipidemic patients.

Both "big" platelets and hyperlipidemia are associated with increased coronary risk. This study was undertaken to search for a possible effect of various hypolipidemic drugs on big platelets. The percentage of big platelets, assessed microscopically, was measured in 66 patients who had hyperlipidemia of various types. Twenty-seven patients with hypertriglyceridemia were randomly selected to receive either fish oil or placebo in a crossover study. Another group of 39 patients with hypercholesterolemia, among them 13 with heterozygous familial hypercholesterolemia (FH), received lovastatin. The pretreatment level of big platelets was elevated, and similar in all groups: 23.3 +/- 12% versus 22 +/- 9%, in the fish oil versus placebo group, 19.1 +/- 6.3% versus 24 +/- 11% in the FH versus non-FH primary hypercholesterolemia group (reference value, 6.8 +/- 3.5%). After treatment, despite the improvement in lipoprotein profile, the percentage of big platelets did not change. The relationship between lipid reduction and big platelets is thus questionable, and necessitates further study.

Aged↗
PubMed1992

Partial suppression of cell mediated immunity in chromoblastomycosis.

The cellular immune response of 8 patients from the Brazilian Amazon region with chromoblastomycosis was analyzed. Primary immunological responses of patients were tested by contact sensitization to 2,4-dinitro-chlorobenzene (DNCB), or rejection of first set skin allografts. 2 of 8 patients were reactive to DNCB after sensitization, and skin allograft rejection occurred in an average of 14 days. Capacity of patients to mount recall immunological responses was measured by skin testing with two fungal antigens and three bacterial antigens. Delayed skin reaction to trichophytin and candida antigens was negative in the majority of the patients. However, reactivity to mycobacterial (tuberculin), and bacterial (staphylococcal, streptococcal) antigen was high, or only slightly diminished respectively. The data suggest that patients with chromoblastomycosis have suppressed nonspecific, cell mediated immunity for some antigens (skin allografts, DNCB, fungal antigens), while reactivity to bacterial and mycobacterial antigens is not impaired.

Aged↗
PubMed1992

Major thoracic surgery during long-term extracorporeal lung assist for treatment of severe adult respiratory distress syndrome (ARDS).

Surgery in patients treated with extracorporeal lung assist (ELA) carries a high risk of life threatening bleeding complications caused by the need for systemic anticoagulation. A case report describing a successful surgical intervention for the repair of a broncho-pleural leakage by thoracotomy during ELA is presented. A newly developed heparin coated extracorporeal system was used in a patient being treated for severe adult respiratory distress syndrome (ARDS) after left sided pneumectomy. The heparin coated system allowed discontinuation of systemic heparinization intraoperatively without coagulation complications related to the extracorporeal system. This procedure was followed by resolution of the ARDS.

Adult↗
PubMed1992

Ultrastructural study of sex inversion in a protogynous hermaphrodite, Epinephelus microdon (Teleostei, Serranidae).

Sex inversion of Epinephelus microdon, a protogynous hermaphrodite was studied using light and electron microscopic criteria. The sex changes takes place within ex-ovarian lamellae in which, in addition to spermatogonia, numerous primordial germ cells (PGCs) were detected. These undifferentiated and bipotential early germ cells are involved, as well as spermatogonia, in the building up of the testis.

Animals↗
PubMed1992

Electron paramagnetic resonance (EPR) imaging in skin: biophysical and biochemical microscopy.

Electron paramagnetic resonance (EPR) is a spectroscopic technique that allows detection of paramagnetic compounds, e.g., free radicals, in skin, and is used for measuring skin membrane fluidity and polarity. EPR imaging is concerned with spatially resolved EPR spectroscopy. We studied EPR images at X-band frequency (9 GHz) in the skin biopsies of hairless mice. Our particular imaging technique utilized a modulated field gradient to obtain cross-sectional images perpendicular to the skin surface. Employing nitroxide free radicals, this approach allows analysis of skin biophysical and biochemical features at the micrometer resolution level. By spin labeling drugs, pharmacokinetic properties of the labeled compound can be monitored in skin. We suggest that EPR imaging has a broad application potential in dermatologic research. In comparison to other spatially visualizing techniques, such as nuclear magnetic resonance (NMR) imaging and ultrasound, EPR imaging has significant advantages, such as high spatial resolution and providing specific biochemical and biophysical information that cannot be obtained by other methods in skin.

Animals↗
PubMed1992

Glaucoma blindness in Denmark.

In order to evaluate the prevalence and the incidence of glaucoma blindness in Denmark, all registration forms of persons greater than or equal to 50 years of age at admission, admitted to the Danish Association of the Blind (DAB) between 1955 and 1987 with glaucoma as main cause of blindness, were examined. In 1987 6.7% of DAB-members greater than or equal to 50 years of age suffered from blindness caused at least partially by glaucoma, equivalent to an estimated prevalence of 45 per 100,000 of the Danish population greater than or equal to 50 years. The estimated annual incidence of blindness due to glaucoma was 7 per 100,000 greater than or equal to 65 years, and in an equal number of patients glaucoma was a contributory cause of blindness. The incidence of blindness due to glaucoma was decreasing in the young age groups (less than 65 years) throughout the study period. Glaucoma blindness seems to occur at a later age now than earlier, leaving the patients blind for a shorter time. This pattern may be explained by improved health services but could also be due to a change in the spontaneous course of glaucoma. The proportion of glaucoma blindness in the glaucoma population was estimated to be 4-5%.

Age Factors↗
PubMed1991

Crystal structure of a Y35G mutant of bovine pancreatic trypsin inhibitor.

The structure of a Y35G mutant of bovine pancreatic trypsin inhibitor (BPTI) was solved by molecular replacement and was refined by both simulated annealing and restrained least-squares at 1.8 A resolution. The crystals belong to the space group P42212, with unit cell dimensions a = b = 46.75 A, c = 50.61 A. The final R-factor is 0.159 and the deviation from ideality for bond distances is 0.02 A. The structure of the mutant differs from that of the native protein, showing an overall root-mean-square (r.m.s.) difference of 1.86 A for main-chain atoms. However, the change is mostly localized in the two loops (respective r.m.s. values of 2.04 A and 3.93 A) and the C terminus (r.m.s. 6.79 A), while the core of the protein is well conserved (r.m.s. 0.45 A). The change in the loop regions can be clearly attributed to the mutation while the difference in the C terminus might be only due to a different crystal packing. Seventy water molecules were included in the model but only seven of them are shared with the native structure. Thermal parameters are showing a good correlation with those for the wild-type of BPTI.

Amino Acid Sequence↗
PubMed1991

Transient ischemic attack-related syncope.

The records of 483 patients admitted to the emergency room because of syncope were reviewed. Thirty seven patients (7.7%) were found to suffer from transient ischemic attack- (TIA) related syncope. This group is the subject of this report. Of these patients, 28 (76%) were men (mean age 71 years). Seven patients reported previous syncopal episodes. Past history revealed a high rate of ischemic heart disease (70%) and hypertension (68%). Concurrent neurologic symptoms, which led to the diagnosis of TIA-related syncope, included mainly vertebrobasilar symptoms: vertigo (in 55% of the patients), ataxia (46%), parasthesia (41%). Two patients most probably were presenting bilateral carotid artery disease. Various diagnostic tests (including electroencephalography, computed tomography, sonography, and cerebral angiography) were used to exclude other causes of syncope. During follow-up (mean 14.5 months) four patients (11%) had an additional episode of TIA and in three of them syncope reappeared. One patient had a complete stroke. We conclude that TIA is a much more frequent explanation for syncope than has been previously argued. These patients tend to be elderly males with high incidence of ischemic heart disease and hypertension. The concurrent neurologic symptoms, leading to the diagnosis, represent mainly vertebrobasilar territory ischemia.

Aged↗
PubMed1991

Lovastatin therapy in hypercholesterolemia: effect on fibrinogen, hemorrheologic parameters, platelet activity, and red blood cell morphology.

The effect of lovastatin therapy on blood rheology was investigated in 26 hypercholesterolemic patients. Treatment with lovastatin was associated with a significant improvement in whole blood filtration time and a tendency toward normalization in red blood cell morphology. A significant increase was observed in fibrinogen level, in ADP-induced platelet aggregation, in the percentage of "big" platelets, and in platelet count. The viscosity of whole blood and plasma and the percentage of aggregated platelets did not change significantly. The cause for these hemorrheologic changes and their role in influencing the coronary risk of lovastatin-treated hypercholesterolemic patients should be further investigated.

Adolescent↗
PubMed1991

Oxidative imbalance in HIV infected patients.

We present an outline of the complex interplay of oxidants and antioxidants in infectious diseases in general, and in particular with reference to the HIV infection, and subsequent opportunistic infections. Viral and opportunistic infections may directly or indirectly cause an imbalance in prooxidant/antioxidant mechanisms and result in generation of increased steady state concentrations of reactive oxidants. In HIV patients a prooxidant state could lead to a self-perpetuation of infection via stimulated expression of genes carrying the virus genome, and subsequently to immunosuppression, and promotion of initiated cells to neoplastic growth.

Antioxidants↗