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Biomedical subjects

A Brock

Publications and source records attributed to A Brock.

At least 37 records · Page 2Linked to original sources
PubMed1994

alpha-Amylase in resectable lung cancer.

Biochemical analysis and immunohistochemical techniques support the theory that hyperamylasaemia in lung cancer is due to amylase production in carcinoma cells. The vast majority of amylase-producing carcinomas are adenocarcinomas with amylase isoenzyme similar to the salivary type. This prospective study assesses alpha-amylase expression in resectable lung cancer. Seventy four patients with resectable lung cancer were studied. Amylase activity in tumour tissue was analysed and isoamylase identification performed. Immunohistochemical analysis was performed using a polyclonal rabbit antibody against human salivary amylase. Hyperamylasaemia occurred in 13 out of 70 patients. Increased amylase activity in tumour tissue was found in 10 out of 52 cases, of which only two were associated with hyperamylasaemia. With the exception of one large cell carcinoma and one squamous cell carcinoma, the tumours were adenocarcinomas. Immunohistochemical analysis revealed amylase expression in seven adenocarcinomas and two adenosquamous carcinomas. In conclusion, immunohistochemical amylase expression was restricted to carcinomas with adenomatous differentiation. Biochemical analysis confirmed amylase production in 5 of 7 cases examined, the tissue amylase isoenzymes being of salivary type. However, hyperamylasaemia and a slightly increased amylase activity in tumour tissue may be caused by factors other than amylase-producing carcinoma cells.

Adenocarcinoma, Papillary↗
PubMed1994

[The methods and results of simultaneous radiochemotherapy with carboplatin in advanced cervical carcinomas].

PURPOSE: The frequency and the poor therapeutic results in advanced cervical cancer establish the demand for effectiveness of treatment. Recent clinical data have shown that simultaneous radiochemotherapy may yield high remission rates in squamous cell carcinomas of other organs. PATIENTS AND METHODS: In our Department of Radiotherapy and Radiooncology of the University of Leipzig we treated since 1.6.1991 17 patients with advanced cancer of the uterine cervix with a simultaneous radiochemotherapy with carboplatin. RESULTS: The rate of complete remission was 76%. Follow-up is available from six to 24 months. Severe or toxic side effects of the treatment we didn't observe. Eight (47%) patients live relapse-free. CONCLUSIONS: In our opinion randomized studies are required to determine: What is better? Simultaneous radiochemotherapy or radiotherapy?

Adolescent↗
PubMed1993

Factors affecting inter-individual variation in human plasma cholinesterase activity: body weight, height, sex, genetic polymorphism and age.

The influence of body weight, height, age and sex on plasma cholinesterase activity (ChE) in 650 males and 437 females with ChE-1 phenotype U (genotype ChEuChEu or ChEuChEs) or UA (genotype ChEuChEa) was studied in a multiple regression model. ChE was not influenced by age (p > 0.01), but, like other liver synthesized plasma enzymes, highly (p < 0.001) influenced by body weight and height. In a logarithmic scale ChE followed a linear model (R = 0.535, p < 0.001) with randomly distributed residuals, InChE = 3.286-0.308 x ChE-1 phenotype-0.104 x sex + 0.00765 x weight - 0.00723 x height (U = 1, UA = 2; male = 1, female = 2; kg; cm). A simplified model based on body-mass index (BMI = weight divided by squared height, kg/m2), InCHE = 2.016-0.308 x ChE-1 phenotype - 0.091 x sex + 0.0230 x BMI, showed the same goodness-of-fit (R = 0.533). In a non-logarithmic scale both multiple regression models failed to fit cases with high ChE activity. A model for a 'standardized' plasma ChE in which the effects of ChE-1 phenotype, sex, body weight and height are eliminated, is proposed to compare ChE in unmatched population groups when using this enzyme activity as a biomarker in environmental or occupational medicine.

Adolescent↗
PubMed1993

Distribution of hydroxylated vitamin D metabolites [25OHD3 and 1,25(OH)2D3] in domestic pigs: evidence that 1,25(OH)2D3 is stored outside the blood circulation?

1. The distribution of 25-hydroxycholecalciferol (25OHD3) and 1,25-dihydroxycholecalciferol [1,25(OH)2D3] in various organs from domestic pigs was examined by HPLC. 2. Plasma levels of both metabolites corresponded to those found in healthy human subjects. 3. Tissue concentrations of 25OHD3 in fat, kidney, liver, and intestinal mucosa were low (< 1/3 of plasma levels), whereas tissue concentrations of 1,25(OH)2D3 exceeded plasma levels by factors 3-7, adipose tissue concentrations being the highest. 4. Substantial amounts of activated vitamin D are stored outside the blood-streams and may actively participate in vitamin D and calcium homeostasis.

Animals↗
PubMed1993

Ki-S1, a novel proliferative marker: flow cytometric assessment of staining in human breast carcinoma cells.

There is considerable interest in immunohistochemical markers of proliferation which are suitable for use on routinely fixed clinical material. The novel proliferation-associated antibody Ki-S1 shows promise in this respect. In this study we have: (i) defined the pattern of Ki-S1 labelling relative to the cell cycle phase; (ii) investigated the labelling pattern with Ki-S1 on a human breast cell line (ZR75) under varying proliferative conditions induced by serum deprivation and refeeding; (iii) examined in a flow cytometric study Ki-S1 staining in archival, clinical breast carcinoma samples. In exponentially growing cells Ki-S1 showed a marked cell cycle phase-specific variation in staining intensity which increased linearly through the S-phase, was high in G2 and reached its peak in mitosis. Ki-S1 staining intensity mirrored the changes in proliferative activity of ZR75 cells during serum deprivation and refeeding. In a small series of human breast carcinoma, Ki-S1 staining intensity correlated with S-phase fraction (SPF) derived from DNA profiles. The antigen labelled by Ki-S1 is extremely robust, resisting degradation by fixation and by an aggressive enzymic tissue disaggregation method. Ki-S1 warrants further investigation as a proliferation-related marker, particularly for routine clinical application.

Animals↗
PubMed1993

Unchanged noradrenaline reactivity and blood pressure after corrective surgery in primary hyperparathyroidism.

In order to evaluate the role of the hyperparathyroid state for blood pressure and volume homeostasis, eight patients with primary hyperparathyroidism were studied before and after corrective surgery. Neither noradrenaline induced blood pressure changes nor basal blood pressure were affected by the operation, and the values were the same as in an age- and sex-matched control group. Noradrenaline infusion induced an increase in PTH(1-84) values before (72-86 ng l-1, medians, p < 0.02), in contrast to a decrease after (28 to 19 ng l-1, p < 0.05) operation for primary hyperparathyroidism. Basal plasma atrial natriuretic peptide was lower before than after removal of adenomata (3.2 vs. 4.8 pmol l-1, medians, p < 0.02). Cyclic 3'-5'-guanosine monophosphate was not significantly changed (4.7 vs. 5.5 nmol l-1). Aldosterone was higher before than after surgery (139 vs. 71 pmol l-1, p < 0.02), whereas angiotensin II was unaltered (20 vs. 9 pmol l-1). Arginine vasopressin was higher before than after the operation (0.9 vs. 0.7 pmol l-1, p < 0.05), but urinary excretion of prostaglandin E2 was unchanged. In conclusion primary hyperparathyroidism was not associated with changes in noradrenaline reactivity or basal blood pressure despite derangements of hormones adjusting sodium and water homeostasis. It is suggested that the hormonal changes may be secondary to a relative volume depletion.

Adult↗
PubMed1992

Anti-cholinesterase agents uptake during cultivation of greenhouse flowers.

The cholinesterase (ChE) activities were measured in-season and out-season in a total of 204 greenhouse workers and 360 non-exposed controls. No seasonal ChE variation were observed in the controls, whereas an in-season depression was seen in the workers, indicating an uptake of anti-cholinesterase agents during cultivation of greenhouse flowers in the intervals between sprayings (p = 0.0001). The anti-ChE agents applied seem to persist in the greenhouses and cause continued subtoxic uptake for weeks since last application. Wearing of protective gloves did not prevent the uptake. Thus, chronic percutaneous and oral uptake occurs as a result of cultivation of greenhouse flowers.

Carbamates↗
PubMed1992

Cadmium effects on bone metabolism: accelerated resorption in ovariectomized, aged beagles.

The purpose of this study was to evaluate, in an animal whose skeleton is comparable to humans, the combined effects of estrogen depletion and Cd exposure on bone resorption by monitoring skeletal release of 45Ca and to determine whether Cd-induced bone resorption occurred independent of osteotropic hormone changes and renal dysfunction. Cd exposure following ovariectomy or sham surgery was for 7 months: 1 month by oral ingestion of capsules (1, 5, 15, 50 ppm) and 6 months via drinking water (15 ppm). Serum and fecal 45Ca were increased at 1 week following ovariectomy (OV) (54 +/- 9% and 122 +/- 40%, respectively), but this response was attenuated by 2 weeks. Five of seven exposed dogs had increased serum and fecal 45Ca during the 50-ppm Cd capsule period (15-40% and 15-190%, respectively). Serum 45Ca levels in OV/+Cd dogs showed a significant and consistent increase within 1 week of initiating each of three separate Cd.H2O exposure cycles. Blood Cd levels increased over time from 2 to 15 micrograms/l, coinciding with the elevated serum 45Ca concentrations. No correlation was observed between serum 45Ca increases and parathyroid hormone, 1,25-(OH)2-vitamin D, or calcitonin. No effects of ovariectomy and/or Cd were observed in total serum Ca, calciotropic hormone concentrations, serum or urinary phosphorus and creatinine, creatinine clearance, or urinary specific gravity. Urinary Cd concentrations ranged from 7 to 50 micrograms/l in exposed dogs but were not detectable in nonexposed dogs. Urinary protein concentrations showed no differences between groups. Cd increased bone resorption (skeletal 45Ca release) in ovariectomized and sham-operated dogs without renal dysfunction or calciotropic hormone interaction. Based on our results, Cd is an exogenous factor which exacerbates bone mineral loss in postmenopausal osteoporosis.

Aging↗
PubMed1992

Chronic subclinical intake of dietary anticholinesterase agents during the spraying season.

The dietary intake of anticholinesterase (anti-ChE) agents was estimated in 331 schoolteachers during the spraying season. Summer plasma-cholinesterase (ChE) activity was compared with the baseline value obtained during winter. Intraindividual plasma-ChE activity varied independently of factors such as drugs, non-malignant diseases, alcohol and smoking. A depressed mean plasma-ChE, indicating an intake of anti-ChE agents (P = 0.04), was observed in individuals who consumed exclusively agriculturally-grown fruits and vegetables without an additional intake of unsprayed, home-grown products. It remains to be determined whether a subclinical but chronic intake of anti-ChE agents in the diet can be hazardous to humans.

Cholinesterase Inhibitors↗
PubMed1992

Flow cytometric characterisation of proliferating cell nuclear antigen using the monoclonal antibody PC10.

Anti-PCNA antibodies have aroused considerable interest recently as potential immunohistochemical markers of proliferation for use on clinical samples. PC10 is a monoclonal antibody which has been shown to recognise its epitope on formalin-fixed, paraffin-embedded, archival material. However, whilst PC10 gives the expected labelling pattern for growth fraction in normal tissues and some tumours, discrepant results have been obtained, for example, in carcinoma of the breast. By means of flow cytometry, we have attempted to characterise the different staining patterns that can be obtained with PC10. Intact fixed cells from proliferative mammalian cultures show 100% labelling, consistent with a growth fraction estimate. In contrast, detergent-extracted nuclei show S-phase specific staining. Nuclei extracted by treatment of fixed cells with pepsin show a different staining pattern again, with many G1 cells weakly stained and staining intensity increasing through S-phase into G2. The results demonstrate that multiparametric flow cytometry can define the cell populations which label with proliferation-related antibodies, such as PC10, under a variety of experimental conditions.

Animals↗
PubMed1992

A new automated method for phenotyping arylesterase (EC 3.1.1.2) based upon inhibition of enzymatic hydrolysis of 4-nitrophenyl acetate by phenyl acetate.

A new method for phenotyping human serum arylesterase (EC 3.1.1.2) is described and evaluated. The aromatic esters, phenyl acetate and 4-nitrophenyl acetate, were compared as substrates for spectrophotometric measurement of arylesterase activity. A method for arylesterase phenotyping, based upon inhibition of the enzymatic hydrolysis of 4-nitrophenyl acetate by phenyl acetate, was developed. The method was applied to serum samples from 158 blood donors and showed a distinct separation of the three phenotypes defined by a reference method based on the ratio of paraoxonase activity to arylesterase activity using paraoxon and phenyl acetate as substrates. The method was adapted to a Cobas-Fara centrifugal analyser.

Alleles↗
PubMed1992

Atrial natriuretic peptide and parathyroid hormone (1-84) in relation to noradrenaline induced changes in blood pressure in uraemic and healthy subjects.

In order to evaluate the hormonal regulation of blood pressure (BP) in uraemia 12 patients on chronic maintenance dialysis and 14 healthy controls were studied. BP and plasma concentrations of atrial natriuretic peptide (ANP), cyclic 3',5'-guanosine monophosphate (cGMP), and intact parathyroid hormone (PTH(1-84)) were determined before, during, and after a 60 min noradrenaline infusion 0.1 micrograms kg-1 body wt. min-1. Mean BP increased to the same extent in the uraemic patients (median 15 mmHg, range 6-25 mmHg) as in the controls (12 mmHg, 5-25 mmHg). ANP increased during noradrenaline infusion both in patients (7.2 to 8.3 pmol/l, medians, p < 0.01) and in controls (4.4 to 6.0 pmol/l, p < 0.01), and so did cGMP (patients: 31.6 to 35.9 nmol/l, p < 0.05; controls: 6.6 to 8.7 nmol/l, p < 0.01). PTH(1-84) was higher in the uraemic patients than in the controls, but was unchanged during noradrenaline infusion in both groups. Correlation analyses gave no evidence of a direct relation between BP and ANP, but basal PTH(1-84) was negatively correlated to basal mean BP in the patients (rho = -0.615, p < 0.05), but not in the controls. In conclusion, noradrenaline induced similar elevations of BP in dialysis patients as in healthy controls despite elevated ANP and PTH(1-84) in the patients, and ANP release was stimulated in both groups. PTH(1-84) may participate in blood pressure regulation in uraemic patients.

Adult↗
PubMed1992

[Radiobiological research to optimize high-dose-rate afterloading therapy with Ir-192 in extragenital tumors].

Since the introduction of the high-dose rate afterloading therapy a higher biological effectivity of this method has been well known in comparison with the low-dose contact therapy. This will practically taken into account by reducing the dose and more fractionating of the total dose. With our test we want: firstly to prove the influence of the therapy break on the duration of the radiation reaction. Secondly we want to prove the influence of the dose rate on the efficiency of the radiation reaction. We have tried to answer the question by the animal model guinea pig skin. We examined early reactions as well late reactions.

Animals↗
PubMed1991

Otto Fenichel and the left opposition in psychoanalysis.

David Rapaport's collection of Otto Fenichel's Rundbriefe (1934-1945) is described as a recently rediscovered, 2,500-page primary source for studying the intellectual and organizational history of European-American psychoanalysis. Beginning as the confidential newsletter of the Reich-Fenichel "Left opposition" within the International Psychoanalytic Association, its function became primarily intellectual as Fenichel's group ceased to function as a caucus. It ended when its editor decided to devote himself to the struggle against neo-Freudianism within psychoanalysis, and to practice as a licensed physician.

Freudian Theory↗
PubMed1991

Inter and intraindividual variations in plasma cholinesterase activity and substance concentration in employees of an organophosphorus insecticide factory.

During a period of 10 months, inter and intraindividual variations in plasma cholinesterase (ChE) activity were studied in 331 employees of an organophosphorus insecticide factory, and in 193 healthy volunteers without occupational exposure to known ChE inhibitors. Repeated (n = 6) measurements of ChE activity and ChE substance concentration were performed in 410 subjects. The study showed substantial intraindividual variations of ChE activity and ChE substance concentration (up to 40%) in the employees and in the reference group. When effects due to sex, ChE-1 phenotype, body weight, and height were considered, one subgroup of employees of the organophosphorus insecticide factory showed a significantly lower average ChE activity than other subgroups; as ChE substance concentrations were found to be proportionally decreased, it was concluded that the low ChE activity was unrelated to occupational exposure. A combined determination of ChE activity and ChE substance concentration is recommended as a rational diagnostic tool when an unexpected decrease of plasma ChE activity is registered in people joining organophosphorus insecticide health surveillance programmes.

Adult↗