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Biomedical subjects

M Marx

Publications and source records attributed to M Marx.

At least 199 records · Page 11Linked to original sources
PubMed1973

Relationship between replication of simian virus 40 DNA and specific events of the host cell cycle.

The relationship between replication of simian virus 40 (SV40) DNA and the various periods of the host-cell cycle was investigated in synchronized CV(1) cells. Cells synchronized through a double excess thymidine procedure were infected with SV40 at the beginning or the middle of S, or in G(2). The first viral progeny DNA molecules were in all instances detected approximately 20 h after release from the thymidine block, independent of the time of infection. The length of the early, prereplicative phase of the virus growth cycle therefore depended upon the period of the cell cycle at which the cells were infected. Infection with SV40 was also performed on cells obtained in early G(1) through selective detachment of cells in metaphase. As long as the cells were in G(1) at the time of infection, the first viral progeny DNA molecules were detected during the S period immediately following, whereas if infection took place once the cells had entered S, no progeny DNA molecule could be detected until the S period of the next cell cycle. These results suggest that the infected cell has to pass through a critical stage situated in late G(1) or early S before SV40 DNA replication can eventually be initiated.

Animals↗
PubMedDate not supplied

Doppler flow profiles in the right and left pulmonary artery in children with congenital heart disease and a bidirectional cavopulmonary shunt.

The systolic and diastolic Doppler tracings in the right and left pulmonary artery were analyzed in 10 patients with complex cyanotic congenital heart disease, aged 6 months to 12 years (median 3 years), after employment of a bidirectional cavopulmonary shunt. The postoperative interval ranged from 2 weeks to 1.7 years (median 1.3 years). In children with pulmonary atresia or severe pulmonary stenosis with minimal antegrade pulsatile pulmonary blood flow Doppler echocardiography confirmed a systolic and diastolic bidirectional shunt from the vena cava superior to both pulmonary arteries. In children with pulmonary stenosis, Doppler echocardiography confirmed a systolic shunt only to the right pulmonary artery and a diastolic bidirectional shunt into both pulmonary arteries. As the left pulmonary artery was perfused by the pulsatile transvalvular flow it was difficult to detect a concomitant systolic Glenn-related flow in those patients. Quantitative analysis of the diastolic Doppler tracings revealed a significant difference in the velocity time integral in the right and left pulmonary artery indicating a dominant right lung perfusion in diastole.

Arteriovenous Shunt, Surgical↗
PubMedDate not supplied

Successful reversal of hepatic encephalopathy with intentional occlusion of transjugular intrahepatic portosystemic shunts.

PURPOSE: To establish a safe and effective method for occluding a transjugular intrahepatic portosystemic shunt (TIPS) in patients who develop uncontrollable, disabling encephalopathy. PATIENTS AND METHODS: The study population consisted of five patients who developed refractory encephalopathy following TIPS. The indication for TIPS was bleeding in four patients and ascites in one. Wallstents that were 10 mm in diameter and 68 mm long were used to bridge the hepatic parenchyma in all patients. The onset of encephalopathy from the time of the TIPS procedure ranged from 24 hours to 210 days. Because encephalopathy was not responsive to conventional medical management, shunt thrombosis was induced by means of temporary inflation of an 11.5-mm-diameter latex occlusion balloon within the midportion of the stent. RESULTS: All shunts were successfully thrombosed when the balloon was inflated for 12 hours or more. Encephalopathy resolved in four patients and improved in the remaining patient. One patient experienced recurrent bleeding within 24 hours of the TIPS occlusion that was controlled medically. CONCLUSION: Temporary occlusion of a TIPS with latex balloons successfully induces shunt thrombosis and improves encephalopathy. However, the patient is again exposed to risks related to complications of portal hypertension.

Adult↗
PubMedDate not supplied

[Late hormonal complications after brain tumor treatment in childhood and adolescence: literature review and a model of integrated hormone aftercare].

The variety of endocrine late-effects after brain tumour therapy in childhood is well known. Growth is usually impaired first due to a hypothalamo-pituitary growth hormone (GH) deficiency or a radiation-induced neurosecretory dysfunction of GH secretion. Generally, all hypothalamo-pituitary axes can be affected. Disturbances of puberty, gonadal function, thyroid function and adrenal function can manifest after a long posttherapeutic interval. A retrospective analysis of the auxological and endocrinological data assessed within the German brain tumour study HIT 91 showed that endocrinological follow-up of these patients was not satisfactory. Therefore we have developed a concept for the new brain tumour study: auxological and laboratory parameters will be assessed before oncological therapy and in regular intervals (4, 12, 18, 24 months after the end of tumour therapy). 24 months after the end of tumour therapy all hypothalamo-pituitary axes are to be evaluated with pharmacological stimulation tests.

Aftercare↗
PubMedDate not supplied

L-arginine reduces kidney lipid peroxidation, glycoxidation and collagen accumulation in the aging NMRI mouse.

Collagen accumulation in organs is a main feature of the physiological aging process. There are two main theories for the responsible mechanisms, the free oxygen radical and the glycoxidation theory. Both lead to carbonyle-induced protein modification, increased collagen cross-linking and subsequently to the collagen accumulation. In previous studies we provided evidence for the blocking of reactive carbonyles by L-arginine in the diabetic state and present here data for this effect in the aging NMRI mouse. NMRI mice were fed L-arginine in tap water for a period of 6 months and compared to an untreated control group. Kidney collagen content of the treated group was significantly reduced (treated: 8.83 +/- 0.72 mg collagen/100 mg kidney weight; untreated: 11.95 +/- 0.98 mg collagen (100 mg kidney weight; p < 0.05). Using a colorimetric assay for lipid peroxidation products we found significantly reduced lipid peroxidation-derived aldehydes in the treated group (treated: 0.25 +/- 0.03 extinction; untreated: 0.36 +/- 0.04 extinction; p < 0.05). The parameter for glycoxidation, N-epsilon-carboxymethyllysine (CML) was significantly lower in the experimental group as well (treated: 2.3 +/- 0.5 nM CML/microM hydroxyproline; untreated: 4.3 +/- 0.52 nM CML/microM hydroxyproline; p < 0.05). No differences were observed for the biomarker of hydroxyradical attack, o-tyrosine. L-Arginine could have reduced collagen accumulation by blocking collagen glyc(oxidation) which is known to lead to increased collagen cross-linking, solubility and degradation as a strong correlation between both CML and collagen content (r2 = 0.654, p < 0.05) as well as between lipid peroxidation products and collagen content (r2 = 0.539, p < 0.05) was observed.

Aging↗
PubMedDate not supplied

A boy presenting with familial short stature--diagnosis Gitelman syndrome.

Patients with Gitelman syndrome are usually diagnosed by chance or present with muscular weakness, constipation, or tetanies due to hypokalemia and hypomagnesemia. We present a short statured boy with a clear history of familial short stature, normal growth and a final height prognosis within the target height range. However, routine laboratory studies led to the diagnosis of Gitelman syndrome. If a baseline laboratory analysis had not been performed, this diagnosis would have been missed.

Body Height↗