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Biomedical subjects

D Becker

Publications and source records attributed to D Becker.

At least 235 records · Page 13Linked to original sources
PubMed1991

[New principles of using biodegradable implants in the treatment of fractures].

So far the operative treatment of bone fractures has resolved itself to immobilisation and bone fragment joining with the help of metal implants such as nails, screws, plates and wires. Once the bone had healed, they had to be removed. This action bears some risk, e.g. extremity disfunction, wound infection. This requires re-hospitalization and increases social cost of the treatment. These reasons gave rise to research on new, biodegradable materials. One of them is "Biofix" manufactures as threads or nails, employed when immobilising bone fragments. Application of "Biofix" allows early rehabilitation. In 200 cases we utilized "Biofix" reinforced with a wire loop, which brought about positive results. In isolated cases there occurred inflammation of the tissues that surrounded the implant during its biodegradation. The surrounded tissues exhibited an acid reaction of pH 3-4. The biodegradable material "Biofix" is sensitive to torsion, which hinders making screws of it, hence the method of using it for nails, wire and thread. This issue is dealt with the Kampere Technical University.

Adult↗
PubMed1991

Basic fibroblast growth factor in human melanoma.

Basic fibroblast growth factor (bFGF) is a major factor contributing to human melanoma cell growth. bFGF is produced constitutively by cells from each stage of the disease, but not by normal melanocytes, although the latter cells are dependent on the factor for growth in vitro. Two lines of evidence suggest that bFGF functions in an autocrine manner in melanoma: (1) inhibition of bFGF activity by bFGF-specific antibodies or antisense sequences suppresses melanoma cell growth in vitro; and (2) retrovirus-mediated transfer of a bFGF cDNA into normal murine melanocytes renders the recipient cell bFGF-independent. Constitutive production of bFGF is not by itself sufficient for the establishment of the transformed phenotype, however, since bFGF-expressing melanocytes are neither immortalized nor tumorigenic in nude mice.

Fibroblast Growth Factor 2↗
PubMed1990

Excision of a Ds-like maize transposable element (Ac delta) in a transient assay in Petunia is enhanced by a truncated coding region of the transposable element Ac.

The excision of a Ds-like transposable element (Ac delta) is mediated in trans by the transposable element Ac or its derivatives in Petunia protoplasts cotransfected with two plasmid DNAs. Excision restores the activity of the beta-glucuronidase (GUS) gene that is otherwise shut off by the presence of Ac delta in its leader sequence. A transient expression assay (histochemical test) is used to detect the beta-glucuronidase activity at the protoplast to detect the beta-glucuronidase activity at the protoplast level. The number of blue-stained protoplasts is a measure of the excision frequency. With Ac delta alone a near-zero background of GUS activity is detected, which is weakly enhanced by the presence, in trans, of either the wild-type Ac or the coding region (ORFa) transcribed from the 2' promoter of Agrobacterium tumefaciens TR-DNA. A strong enhancement is observed when a truncated Ac coding region, also under the control of the 2' promoter, is supplied in trans. The truncated version has ATG10 at codon 103 in frame with ORFa and is preceded by 7 out-of-frame ATGs. The assay is quick and well suited for detection of excision frequencies above the value obtained with the wild-type Ac. The presence of empty donor sites following excision can be demonstrated by PCR amplification and direct sequencing of the appropriate DNA fragment.

Base Sequence↗
PubMed1990

Mild hypoglycemia associated with deterioration of mental efficiency in children with insulin-dependent diabetes mellitus.

To assess the effects of mild hypoglycemia on cognitive functioning in diabetic children, we used an insulin glucose clamp technique to induce and maintain a hypoglycemic state. Eleven patients, 11 to 18 years of age, completed a series of cognitive tests during a baseline euglycemic state (100 mg/dl (5.5 mmol/L] and repeated those measures at the beginning and end of a hypoglycemic plateau (55 to 65 mg/dl (3.1 to 3.6 mmol/L], and again at restoration of euglycemia. At plasma glucose levels of 60 to 65 mg/dl (3.3 to 3.6 mmol/L), a significant decline in mental efficiency was found. This was most apparent on measures of mental "flexibility" (Trial Making Test) and on measures that required planning and decision making, attention to detail, and rapid responding. Moreover, complete recovery of cognitive function was not contemporaneous with restoration of euglycemia, particularly on those tests requiring rapid responding and decision making (choice reaction time). Not all subjects showed evidence of cognitive impairment during hypoglycemia. The very high degree of intersubject variability suggests that, in addition to plasma glucose values, unknown physiologic variables are responsible for triggering cognitive impairments in school-aged youngsters with diabetes during an episode of mild hypoglycemia.

Adolescent↗
PubMed1990

The formation and structure of the sulfoxyl radicals RSO(.), RSOO(.), RSO2(.), and RSO2OO(.) from the reaction of cysteine, glutathione and penicillamine thiyl radicals with molecular oxygen.

This work reports an electron spin resonance study of the reactions of cysteine, glutathione and penicillamine thiyl radicals with molecular oxygen in frozen aqueous solutions at low temperatures. For all three thiols, the thiyl radical, RS., is found to react with oxygen to form the thiol peroxyl radical, RSOO(.). On the absorption of visible light, RSOO(.) photoisomerizes to the sulfonyl radical, RSO2(.), which subsequently reacts with molecular oxygen to form RSO2OO(.), the sulfonyl peroxyl radical. The identities of the sulfonyl and sulfonyl peroxyl radicals were confirmed by their production by a different route, from sulfinic acid. Sulfinyl radicals, RSO(.), are found as the final radical species in the reactions of thiyl radicals and oxygen. Parallel 17O hyperfine couplings (A parallel) are reported for each sulfoxyl radical and a correlation between the spin density on oxygen and the reactivity of the radical is suggested. As a result of this correlation sulfonyl peroxyl radicals are predicted to be far more reactive than thiol peroxyl radicals. We also report molecular orbital calculations on the nature of the spin density distribution and the molecular geometry of the model radicals CH3SO2(.) and CH3SO2OO(.).

Cysteine↗
PubMed1990

Serum interferon in first psychotic attack.

A group of 34 physically healthy young patients, aged 18-27 years at their first psychotic attack, before neuroleptic treatment and admission, were tested simultaneously with 24 age- and sex-matched controls for levels of serum interferon. No statistically significant differences were found between patients and controls. Therefore, no correlation between acute viral infection and schizophrenia was demonstrated.

Adolescent↗
PubMed1990

Impact of physical fitness and glycemic control on in vivo insulin action in adolescents with IDDM.

The relationship of in vivo insulin-mediated glucose utilization to the state of physical fitness and the degree of glycemic control was examined in 27 adolescents with insulin-dependent diabetes mellitus (IDDM) compared with 10 nondiabetic adolescent control subjects. In vivo total-body insulin-mediated glucose metabolism was evaluated by the hyperinsulinemic-euglycemic clamp. Physical fitness was assessed by maximal oxygen consumption (VO2 max) during cycle ergometry. Patients and control subjects had similar levels of VO2 max (34.9 +/- 8.6 vs. 38.6 +/- 9.9 ml.kg-1.min-1, P = 0.3). Patients had lower total-body insulin-mediated glucose metabolism compared with control subjects (33.9 +/- 14.3 vs. 63.8 +/- 17.2 mumol.kg-1.min-1, P = 0.0002). Among the patients, females had lower total-body insulin-mediated glucose metabolism compared with males (24.2 +/- 2.8 vs. 40.7 +/- 3.4 mumol.kg-1.min-1, P less than 0.001); however, this difference disappeared after correcting for sex differences in fitness levels. Insulin-mediated glucose metabolism correlated with VO2 max in patients and control subjects (r = 0.83, r = 0.81, P less than 0.05). The regression of total-body insulin-mediated glucose metabolism on VO2 max for patients was -2.84 +/- 0.255 VO2 max and for control subjects was 7.12 +/- 0.143 VO2 max, indicating that for similar degrees of physical fitness patients have lower total body insulin-mediated glucose metabolism levels than control subjects. In patients, total-body insulin-mediated glucose metabolism correlated with the degree of glycemic control as assessed by the level of glycosylated hemoglobin (r = -0.63, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Intraoperative digital subtraction angiography and the surgical treatment of intracranial aneurysms and vascular malformations.

Intraoperative digital subtraction angiography using commercially available equipment was employed to confirm the precision of the surgical result in 105 procedures for intracranial aneurysms or arteriovenous malformations (AVM's). Transfemoral selective arterial catheterization was performed in most of these cases. A radiolucent operating table was used in all cases, and a radiolucent head-holder in most. In five of the 57 aneurysm procedures, clip repositioning was required after intraoperative angiography demonstrated an inadequate result. In five of the 48 AVM procedures, intraoperative angiography demonstrated residual AVM nidus which was then located and resected. In two cases intraoperative angiography failed to identify residual filling of an aneurysm which was seen later on postoperative angiography, and in one case the intraoperative study failed to demonstrate a tiny residual fragment of AVM which was seen on conventional postoperative angiography. Two complications resulted from intraoperative angiography: one patient developed aphasia from cerebral embolization and one patient developed leg ischemia from femoral artery thrombosis. This technique appears to be of particular value in the treatment of complex intracranial aneurysms and vascular malformations.

Angiography, Digital Subtraction↗
PubMed1990

Are confinement and treatment synonyms?

The law deals with the question of compulsory confinement, not with compulsory treatment even if sentences are given commenting on the law. The controversy is whether the confinement's aim is to prevent the patient from harming himself and society or to obtain treatment. In the name of humanity the distinction made by the law between the act of hospitalization and treatment robs medicine of its essence so making the psychiatric ward merely a place of custody. The law has to deal with both the confinement and the treatment as synonyms and their application needs no separate consideration and decision. This dilemma will be discussed further based upon appropriate sentences.

Civil Rights↗
PubMed1990

[Function-related reconstruction of chronic syndesmosis ruptures by implantation of a dacron ligament].

Up to now Dacron-Ligaments have been used in repair of the cruciat ligaments of the knee with good success. Specially the good toleration of Dacron by tissue has led us to reconstruct other ligament injuries by Dacron-Ligaments. Seldom but very hindering is an isolated rupture of the syndesmoses for in the first time it will be not diagnosed. But previous ruptures of the syndesmoses can only be treated by reconstruction. In 11 patients we tried to reconstruct the syndesmoses by a special guided Stryker Dacron-Ligament with good results. The operation takes only a short time and is not very invasive. Our following explorations overlook about 4 years and the results will show up a new method for a functional construction.

Adult↗
PubMed1990

Cholesterol screening: comparative evaluation of on-site and laboratory-based measurements.

We measured cholesterol in capillary blood samples from 9683 volunteers over a four-day on-site community screening program, using the "Reflotron" desk-top analyzer (Boehringer-Mannheim Diagnostics, Indianapolis, IN). We also measured cholesterol in venous blood samples from 3% of those screened (a) with the Reflotron at the screening sites, (b) in a qualified hospital clinical laboratory, and (c) in a Centers for Disease Control standardized lipoprotein research laboratory. The sensitivity (and specificity) of the Reflotron measurements, with use of the lipoprotein laboratory measurements as the point of reference, was 0.95 (0.73) in capillary blood samples and 0.88 (0.93) in venous blood samples, compared with 0.99 (0.87) in the hospital clinical laboratory. The Reflotron measurements correlated less well with the lipoprotein laboratory values in both venous blood (r = 0.91) and capillary blood (r = 0.89) samples than did the clinical laboratory values (r greater than 0.99). Furthermore, the capillary blood measurements averaged 7% higher than venous measurements when both kinds of samples were analyzed in the Reflotron.

Adult↗
PubMed1990

Differential expression of protein kinase C and cAMP-dependent protein kinase in normal human melanocytes and malignant melanomas.

Normal human melanocytes, unlike malignant melanomas, require the presence of phorbol ester for growth in culture. Because protein kinase C (PKC) represents the intracellular receptor for phorbol esters, we investigated a possible correlation between expression of PKC and tumor progression in the melanocytic system. The results failed to show expression of PKC-alpha, -beta or -gamma in normal human melanocytes. However, PKC-alpha was expressed in primary and metastatic melanomas; even though antisense oligodeoxynucleotides targeted against different mRNA regions of human PKC-alpha, and H7, an inhibitor of PKC, did not display significant growth-inhibitory effects. A similar pattern of expression was detected with respect to the expression of cAMP-dependent protein kinase (PKA). Normal human melanocytes did not reveal expression of either of the known catalytic or regulatory subunits of human PKA, whereas primary and metastatic melanomas demonstrated expression of the PKA-specific subunits C alpha and RI alpha.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1989

Transforming activity of nasopharyngeal carcinoma DNA detectable in mouse JB6 cells.

A JB6 mouse epidermal recipient cell line has been used to detect nasopharyngeal carcinoma (NPC) DNA-associated transforming activity that is not detectable in the NIH 3T3 focus assay. NPC DNA showed both transforming activity and activity for transferring sensitivity to tumor-promoter-induced neoplastic transformation, assayed in 2 different variants of mouse JB6 cells. Comparison of DNAs from various NPC sources that did or did not harbor EBV DNA and that varied in degree of differentiation showed similar transforming activities and similar activities for transferring promotion sensitivity. Thus both a NPC DNA-associated promotion sensitivity and an oncogenic activity function independently of concurrent EBV gene expression.

Animals↗
PubMed1989

Proliferation of human malignant melanomas is inhibited by antisense oligodeoxynucleotides targeted against basic fibroblast growth factor.

Human malignant melanomas, unlike normal melanocytes, can proliferate in the absence of exogenous basic fibroblast growth factor (bFGF). Exposure of primary melanomas in the vertical growth phase and metastatic melanomas to antisense oligodeoxynucleotides targeted against three different sites of human bFGF mRNA inhibited cell proliferation and colony formation in soft-agar. In contrast, exposure of human bFGF sense or antisense oligonucleotides complementary to human beta-nerve growth factor or insulin-like growth factor I mRNA had no such effects. These experiments indicate that activation of the bFGF gene may play an important role in the progression from melanocytic precursor lesions to malignant melanoma.

Antineoplastic Agents↗
PubMed1989

Spontaneous whole blood platelet aggregation in insulin-dependent diabetes mellitus: an evaluation in an epidemiologic study.

Spontaneous whole blood platelet aggregation (SWBPA) was examined in a case-control study, comparing a consecutive series of IDDM subjects (n = 30) to age, and sex matched controls. Subjects were free of platelet altering medications. Platelet aggregation was measured by the percent fall in single platelet count after 15 minutes of both shaking (SK) and magnetic stirring (ST). IDDM subjects showed a significantly greater percent fall in SK (means = 12.1) and ST (means = 34.0) compared to controls (SK means = 8.4, p less than 0.01; ST means = 24.3, p less than 0.05). Long-term repeat testing on 15 subjects (diabetics and non-diabetics) up to 4 months apart showed a correlation of 0.7 for SK, p less than 0.01 but only 0.4 for ST. In a further series of IDDM subjects (n = 176) those with macrovascular disease (n = 27) showed significantly greater percent fall in SK (p less than 0.05), and ST (p less than 0.05). We conclude that SWBPA is a simple useful epidemiological technique (shaking being more repeatable than stirring) which relates to both diabetes and macrovascular disease.

Adolescent↗