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Biomedical subjects

R Becker

Publications and source records attributed to R Becker.

At least 73 records · Page 4Linked to original sources
PubMed1986

Determination of tramadol in human serum by capillary gas chromatography with nitrogen-selective detection.

A specific, sensitive and precise method for the determination of tramadol in human serum is described. It comprises a three-step extraction procedure and a specific determination by capillary gas chromatography with nitrogen-selective detection, using a homologue of tramadol as an internal standard. The specificity of the method was checked by gas chromatography-mass spectrometry. Precision parameters were 1.7-5.5% (within-run) and 3.2-5.7% (between-run) in the concentration range 12.5-200 ng/ml. The detection limit was about 3 ng/ml.

Chromatography, Gas↗
PubMed1986

Poststroke depression and lesion location. An attempted replication.

Recent evidence suggests that poststroke depression is associated with the location of the brain infarct, proximity to the frontal pole being associated with greater depression following left hemisphere injury, and an opposite relationship being seen with injury to the right hemisphere. This study was designed to replicate and extend previous investigation of this issue. Depression was assessed following recent stroke in patients with localized right (n = 16) or left (n = 19) hemisphere lesions. No overall differences between these groups were found on several measures of depression. Although there appeared to be a negative linear relationship between severity of depression and distance of the lesion from the frontal pole in left hemisphere patients, this association failed to attain statistical significance. A curvilinear relationship was evident in right hemisphere patients, with anterior and posterior lesions associated with high depression scores. These data support the notion that lesion location is associated with the severity of poststroke depression, although the nature of this association may be more complex than has previously been suggested.

Aged↗
PubMed1986

A statistical method for determining suitability for community placement.

The authors developed a statistically based method for determining whether inpatient or outpatient placement is most appropriate for a given patient. This study assesses the method's accuracy by comparing statistical classifications of a random sample of inpatients at five New York State facilities with the classifications of multidisciplinary clinical teams. The statistical method proved to be very strong in screening patients who should not be considered for community placement and in four of the five facilities was also strong in identifying appropriate outpatients. The authors discuss the method's implications for outpatient screening and outpatient programs.

Community Mental Health Services↗
PubMed1986

Value of magnetic resonance imaging in the evaluation of patients with complete and high degree block due to intracanal neoplasm.

Magnetic resonance imaging (MRI) of 26 patients with high degree or complete epidural and/or intradural myelographic block, due to primary or secondary neoplasm were analysed. The ratio of false negative MRI was 11.5 per cent. MRI findings were considered to be indicative of lesser block than indicated by myelography in almost 50 per cent of patients. Correlation between the two modalities was highest in cases associated with significant vertebral collapse, malalignment and angulation of the spine and angulation of the spinal cord.

Humans↗
PubMed1986

[Rehabilitation following surgery of intraspinal tumors of the thoracic spine].

17 patients were operated on because of a spinal compression by tumour. Postoperatively, all patients had an incomplete paraparesis, 11 patients were bed-ridden and needing care, 12 had a rectovesical incontinence. On an average 3 months after intensive physiotherapy, 14 patients could walk without or with little help, only 2 had no control of faeces or urine. In general, the postoperative rehabilitation needs a long time, but has an encouraging prognosis.

Adolescent↗
PubMed1985

The concentrations of 6-keto-PGF1 alpha and TXB2 in plasma samples from patients with benign and malignant tumours of the breast.

Peripheral plasma concentrations of 6-keto-PGF1 alpha and TXB2 were measured in patients with benign and malignant tumours of the breast, in patients with non-gynecological diseases, and in healthy female controls. The values were significantly higher in female patients with malignant tumours of the breast than in healthy controls (146 +/- 28 vs 13 +/- 2.5 pg/ml for 6-keto-PGF1 alpha p less than 0.01 and 78 +/- 17 vs 11 +/- 2 pg/ml for TXB2, p less than 0.01). Benign tumours of the breast were also associated with significantly raised plasma levels of 6-keto-PGF1 alpha and TXB2 compared to normal controls (52 +/- 5 vs 13 +/- 2.5 pg/ml for 6-keto-PGF1 alpha, p less than 0.01 and 26 +/- 5 vs 11 +/- 2 pg/ml for TXB2, p less than 0.05). The high levels of 6-keto-PGF1 alpha and TXB2 were not found to be correlated with clinical and histopathological data. The surgical removal of the primary tumour has apparently no effect on the plasma concentrations of 6-keto-PGF1 alpha and TXB2 over a follow-up period of 9 days after operation. The lack of alterations in the ratio of TXB2:6-keto-PGF1 alpha in the cancer patients and other subjects studied before and after surgery is indicative of the regulatory power of metabolic systems to preserve the homeostatic balance.

6-Ketoprostaglandin F1 alpha↗
PubMed1985

Influence of sulfasalazine, 5-aminosalicylic acid and sulfapyridine on prostanoid synthesis and metabolism in rabbit colonic mucosa.

The effects of sulfasalazine (SASP) and its cleavage products 5-aminosalicylic acid (5-ASA) and sulfapyridine (SP) on prostanoid (PG) synthesis and degradation were determined in rabbit colonic mucosa fractions in vitro. When the microsomal fraction was incubated with (14C)arachidonic acid, 10(-3) M SASP and SP did not markedly change the formation of labeled PGE2, PGF2 alpha, TxB2 and 6-keto-PGF1 alpha X 10(-4) M 5-ASA increased synthesis about 2.7-fold; the pattern of PG identified was unaltered. In the presence of the 10-fold higher concentration of 5-ASA, PG synthesis remained elevated at a similar level. When the cytosolic fraction was incubated with (3H)PGE2, 10(-3) M 5-ASA was without influence and 10(-3) M SP decreased slightly PGE2 breakdown. However, SASP showed a pronounced inhibitory effect at 10(-5) M and inhibition of PGE2 degradation was complete at 10(-3) M SASP. The results are compatible with the assumption that stimulation of PG synthesis by 5-ASA is related to therapeutic benefit in the treatment of ulcerative colitis.

Aminosalicylic Acids↗
PubMed1985

Decoration and shadowing of freeze-etched catalase crystals.

Aqueous suspensions of catalase crystals were freeze-cleaved, deep-etched and either shadowed with Ta/W at 45 degrees or decorated with 0.1-0.9 nm thick deposits of Au and Pt at normal incidence. The electron micrographs of the decorated specimens were processed by correlation averaging and compared with a relief reconstruction obtained from shadowed specimens. Pronounced decoration was observed on the catalase crystals at temperatures between 130 and 180 K. Disregarding the difficulties in interpretation, the averages of 0.1-0.2 nm thick Au and Pt films reveal more structural detail than the relief reconstruction. Perfect shadowing provides information on surface topography and is relatively easy to comprehend; decoration renders variations in physico-chemical affinity visible. Problems of the interference of decoration and shadowing effects in the intuitive interpretation of freeze-etch replicas and in relief reconstruction are discussed as well as the disturbing effects of a non-ideal carbon backing. The perspectives of using decoration intentionally as a positive staining technique for the investigation of frozen-hydrated surfaces are evaluated and quality criteria are defined.

Animals↗
PubMed1985

Repair of DNA alkylation adducts in mammalian cells.

Carcinogenic alkylating agents, including nitrosamines, are able to alkylate DNA at various sites. This review presents evidence of the high degree of specificity in the type of DNA damage induced by various N-nitroso compounds and in the DNA repair processes among tissues or cells of different species. The O6-alkylguanine DNA alkyltransferase activity in various human and rodent tissues is discussed as well as the detection of O6-methylguanine in human DNA, using monoclonal antibodies and radioimmunoassay. The relevance of these findings to the mechanisms of cancer induction by nitrosamines is discussed.

Alkylating Agents↗
PubMed1985

A modified hydroxylapatite implant material. A preliminary report.

Hydroxylapatite implants are becoming widely used, but this new material is not without its drawbacks. These mainly concern its physical characteristics, complicating and limiting its clinical applications. A method of altering these with fibrin adhesives is described and early laboratory and clinical experience is presented.

Aged↗
PubMed1984

[Spinal shock in traumatic lesions of the cervical spinal cord. 2 cases].

The spinal syndrome following traumatization of the cervical spine is associated with a typical accident mechanism and predisposing conditions within cervical spine. Two Patients with this syndrome are presented, and the treatment and the need to prevent complications are discussed. Both patients were largely rehabilitated, one returning to work after one year.

Activities of Daily Living↗