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Biomedical subjects

G Hofmann

Publications and source records attributed to G Hofmann.

At least 37 records · Page 2Linked to original sources
PubMed2000

A transient dephosphorylation of JAK1 and JAK2 characterises the early-phase response of murine erythroleukemia cells to the differentiation inducer hexamethylenebisacetamide.

Although dephosphorylation of tyrosine containing proteins is considered a necessary step in the induction of leukemia cell differentiation by hybrid polar compounds (HPC), the crucial actors in this step remain unknown. We present evidence that tyrosine phosphorylation of JAK1 and JAK2 is down-regulated in murine erythroleukemia cells (MELC) within the first 6 h of their exposure to the prototype of the HPC family, hexamethylenebisacetamide (HMBA), with full recovery at 14 h. Further evidence that the JAKs-centered signalling pathway is switched off early by HMBA was provided by the demonstration that STAT5, a downstream member of this pathway, turned out to be completely dephosphorylated at 6 h in HMBA-treated cells. This JAKs dephosphorylation did not occur in HMBA-resistant clones, suggesting that JAKs are possible targets of the dephosphorylative process required for leukemia cell commitment to differentiation. These results may have impact on leukemia therapy based on JAKs inhibitors.

Acetamides↗
PubMed2000

High insulin and low IGF-I plasma levels following pancreas transplantation in rats. Implications for bone and mineral metabolism.

Primary disturbances in mineral metabolism and deficiencies in insulin and insulin-like growth factor-I (IGF-I) have been implicated in the pathogenesis of diabetic osteopenia. This prompted us to investigate whether normal bone minerals and bone morphology are preserved after pancreas transplantation. To this end, 8 inbred rats (transplants) were compared with 9 sham-operated rats (controls) 20 months after orthotopic pancreas transplantation. While basal levels of insulin remained unaffected by transplantation, an oral glucose load elicited hyperinsulinemia (integrated incremental response: mean +/- SEM, 62+/-8 nmol l(-1) 60 min in transplants vs. 32+/-6 nmol l(-1) 60 min in controls; p<0.01) in the presence of normal glucose levels. Fecal and urinary excretion and fractional intestinal absorption of calcium, magnesium and phosphorus, net calcium absorption and the respective serum mineral levels were unchanged after transplantation, as were those of the calciotropic hormones. Serum osteocalcin and bone alkaline phosphatase remained unaffected, and urinary excretion of pyridinium and deoxypyridinium were unchanged. Fasting plasma IGF-I concentration was significantly decreased in transplants (930+/-42 ng ml(-1)) vs. control rats (1074+/-49 ng ml(-1); p < 0.05). Despite similar physical and chemical properties of bone in both groups, histomorphometry revealed slight osteopenia in transplant rats, as reflected by a 38% reduction in the cancellous bone area of the proximal tibial metaphysis. Plasma IGF-I levels were significantly correlated with bone mineral apposition rate (r=0.70, p<0.02), osteoblast perimeter (r=0.60, p<0.05) and osteoid perimeter (r=0.60, p<0.05). In conclusion, pancreas transplantation preserves physical and chemical properties of bone, but bone metabolism is not completely normal after transplantation, as evidenced by decreased cancellous bone. This might have resulted from the insulin resistance associated with the lowering of the plasma IGF-I level, which was correlated with the mineral apposition rate.

Animals↗
PubMed1999

Q.E.D. Alcohol test: a simple and quick method to detect ethanol in saliva of patients in emergency departments. Comparison with the conventional determination in blood.

OBJECTIVE: The aim of this pilot study was to assess whether ethanol concentrations in saliva are comparable to those in blood and to evaluate whether this new non-invasive saliva alcohol test is suitable for use in emergency departments. DESIGN: Prospective, open, non-randomised study. SETTING: University hospital emergency department. PATIENTS AND METHODS: 100 consecutive patients who were admitted to the emergency department whose smell and/or behaviour indicated alcohol abuse. Fifteen patients participated as a control group after they were asked to abstain from alcohol consumption for 24 h before the study. INTERVENTIONS: Blood and saliva samples were obtained at the same time for ethanol measurement. The Q.E.D. Alcohol Test A350 was used in order to measure the concentration of ethanol in saliva. Blood samples were analysed by the alcohol dehydrogenase method. RESULTS: The mean difference between the ethanol levels in blood and saliva was -0.1 mg/dl, whereas the values measured in saliva were on average 0.1 mg/dl higher than those measured in blood (p = 0.002). CONCLUSION: The Q.E.D. Alcohol Test A 350, which uses saliva, is well suited for quantitative determination of alcohol levels. The levels measured in saliva correlate well with those measured in blood at both the lower and the upper end of the scale. Because this test is quick and easy to perform by emergency room personnel and the results are accurate enough for clinical purposes, it should prove valuable to determine whether impaired consciousness is related to alcohol intoxication or to other likely causes.

Adolescent↗
PubMed1997

[Differences in auditory frequency discrimination ability in musicians of different specialties].

The frequency discrimination capacity of 63 musicians of different specialties (singers, string players, wood and brass players, pianists and rhythm teachers) was investigated using a binaural frequency discrimination test. Statistically significant differences between the groups of musicians were found. The string players revealed the highest tuning reproducibility. The results show that frequency discrimination capacity is influenced by specific phenomena of the instrumental education.

Adult↗
PubMed1997

[Cardiac surgery in France (supply, service and needs response): a national survey].

This paper describes the results of a national study of the 70 french cardiac surgery units. This study was required by the ministry of health in order to prepare the planning process of cardiac surgery in France. Results concerning the year 1994 show important regional variations of resources among the country. The number of interventions has increased three fold in 15 years (from 13,000 to 38,000 a year). The share of the different indications are constant (coronaropathy: 53%; valvulopathy: 36%; congenital: 8%). Patient flows across french regions represent 15% of the interventions. Regional intervention rates per capita range from 45 to more than 80 for 100,000 inhabitants. French cardiac surgery is, in fact, organized at a multiregional level and the regional intervention rates are not correlated with mortality or demographic rates.

Cardiac Surgical Procedures↗
PubMed1996

Intraoperative monitoring of the potassium-activity and pH- value on the myocardial surface during coronary bypass surgery.

INTRODUCTION: Ischemic periods very often occur a dysfunction of the heart. In this series the intraoperative changes of potassium-activity and pH- value on the heart undergoing cardioplegic induced cardiac arrest were studied. Furthermore, the sensitivity of the system in diagnostic fields of ischemic periods and reperfusion damages were investigated. METHODS: In eight patients (7 male and 1 female pts.) undergoing elective cardiosurgical procedures (aortocoronary bypass grafts) the ion activity of potassium and hydrogen ions were monitored on the heart, intraoperatively. By ion-selective electrodes the superficial cardiac ion activities were evaluated on definitive time periods on the left (LV) and right ventricle (RV). RESULTS: Preliminary results suggest: In the reperfusion-period different pH-values result on the ventricles. In the end of reperfusion the pH-values return to the starting points. Though the evaluated parameters are too alcaline in comparison to physiological intervals. The time course of epicardial potassium-concentrations is not different between the RV and LV. Initially, only low concentrations were found during perfusion and reperfusion, in the last interval of reperfusion period an increase of potassium on both ventricles were evaluated. In the end of the operations the superficial ion concentrations approximate to the values evaluated at the starting points. CONCLUSION: These results suggests, that the dynamics of ion-exchange-processes in the myocardium can be monitored with the help of ion-selective probes. This new technique opens new strategies in the qualitative check-up of myocardial protective procedures during cardioplegic cardiac arrest.

Coronary Artery Bypass↗
PubMed1996

Intensive care management of acute pancreatitis: recognition of patients at high risk of developing severe or fatal complications.

The clinical spectrum of acute pancreatitis ranges from mild, self-limiting disease of fulminant illness that may rapidly lead to multiple organ failure and death. To identify factors associated with a subsequent severe course and/or high mortality we investigated retrospectively 91 patients admitted to the medical intensive care unit (ICU) with acute pancreatitis during a 2 year period. 67% of the attacks were mild (< or = 1 complication). The overall mortality rate was 9%, whereby 3% of patients with alcoholic and 13% with biliary pancreatitis died. 75% of the patients in the group with a fatal outcome were aged over sixty and 30% in the group with a mild course (p < 0.05). Females with pancreatitis of biliary origin had a mild course in 57% and a severe (> or = 2 complications) or fatal outcome in 43%. In males with alcohol abuse we observed a mild form of pancreatitis in 79% and a severe or fatal course in 21%. The delay between onset of abdominal pain and commencement of treatment in hospital was greater than 12 hours in 70% of all patients studied and there was no association with severity and development of subsequent complications. The median of the acute physiology and chronic health evaluation scoring system (APACHE-III) on the day of admission was 19 in patients with mild disease, which was significantly lower than in patients with severe (40) or fatal acute pancreatitis (53) (p < 0.0001). Serial APACHE-III measurements over 5 days after admission provided further differentiation between mild and severe or fatal cases (p < 0.0001), but no significant difference was observed between survivors with severe course and fatal outcome. In addition, RANSON scores were calculated for comparison with APACHE-III at admission and after 48 hours: concerning the recognition between mild and severe/fatal pancreatitis both scoring systems exhibited similar significant differences on day 1 and day 2. The RANSON scoring system provided further a significant differentiation between survivors with a severe course of pancreatitis when compared to deaths on day 2, whereas the APACHE-III scoring system did not. Advanced age, female sex, biliary obstruction and elevated RANSON and APACHE-III scores are risk factors for an increased rate of life-threatening complications in acute pancreatitis. The daily assessment of such scoring systems may allow the recognition of such patients and may be helpful in the routine clinical management and monitoring of acute pancreatitis.

APACHE↗
PubMed1995

[Receptive musical aptitude using a binaural frequency discrimination test].

Musical aptitude is the most important precondition for any applicant taking up studies at a music conservatory. Thus, the applicants are tested and assessed very thoroughly by experienced music teachers. To support these subjective results by objective data a procedure was developed allowing to test both the examinee's frequency and octave discrimination capacity in a simple way. In a 1-Hz cycle the frequencies f1 and f2 are directed mutually to the right and left ear, respectively, at a defined sound level. Then the examinee is asked to syntonize e.g. frequency equality f1 = f2 (or f1 = 2 x f2). It can be shown that there is a direct correlation between the amount of deviation from nominal frequency and subjective assessment of musicality.

Adult↗
PubMed1995

Evidence for protein damage at environmental temperatures: seasonal changes in levels of ubiquitin conjugates and hsp70 in the intertidal mussel Mytilus trossulus

We examined the seasonal variation in environmentally induced protein damage in natural populations of the intertidal mussel Mytilus trossulus. In order to compare the state of protein pools during seasonal variations in environmental temperature, we used solid-phase immunochemical analysis to quantify ubiquitin conjugate concentrations and relative levels of the stress protein hsp70. The two biochemical indices were selected for their cellular roles in irreversible and reversible protein denaturation, respectively. Proteins that are ubiquitinated are irreversibly damaged and are degraded by intracellular proteases; stress proteins act as molecular chaperones to re-fold thermally denatured proteins and, thus, indicate degrees of reversible protein damage. Comparisons involved mussels collected in February and August from two study sites: an intertidal site which subjected animals to a wide range of body temperatures (from approximately 10 to 35 C in summer), and a subtidal site where animals remained submerged throughout the tidal cycle. Our results show that quantities of ubiquitin conjugates and hsp70 were greater in gill tissue from summer-collected mussels than in gills of winter-collected specimens. Ubiquitin conjugate and hsp70 levels were also greater in mussels collected from an intertidal location than in mussels from a submerged population. Our results show that the high summer temperatures normally experienced in the field are sufficient to cause increased denaturation of cellular proteins. Despite increases in the concentrations of heat shock proteins in summer-acclimatized mussels, elevated levels of irreversibly denatured, i.e. ubiquitinated, proteins were still observed, which indicates that the heat shock response may not be able to rescue all heat-damaged proteins. The energy costs associated with replacing heat-damaged proteins and with maintaining the concentrations and activities of heat shock proteins may contribute substantially to cellular energy demands. These increased energy demands may have an impact on the ecological energetic relationships of species, e.g. in the allocations of energy for growth and reproduction, and, as a consequence, may contribute to determining their distribution limits.

Journal Article↗
PubMed1995

[Problems in differential diagnosis and therapy of intracardiac space-occupying lesions--myxoma and thrombus].

The total removal of the myxoma under extracorporeal circulation from the origin maintains the optimal surgical treatment. Differentiation between myxoma and thromboses is a problem of preoperative diagnostics. Both tumors show unspecific symptoms. Therefore echocardiography and angiography are required as diagnostic tools. Between 1984 and 1991, 14 patients were cured from intracardiac tumors in the Clinic for Cardiovascular Surgery of the University of Leipzig. Problems in the sensitivity and security of the preoperative diagnostics and certain aspects of the surgical treatment will be discussed.

Adult↗
PubMed1994

Congenital varicella syndrome: studies of the virus-specific humoral and cell-mediated immune responses.

We describe a three-year-old boy with congenital varicella syndrome. Persistent IgG antibodies to varicella-zoster virus (VZV) were detected in the child's sera for a period of more than three years. Immunological studies performed at three months and at three years of age showed a VZV-specific cellular immune response. The results suggest that intrauterine VZV infections in early pregnancy can induce adequate humoral and cellular immune reactions in the infected foetus.

Abdominal Muscles↗
PubMed1993

Two bioactive pterocarpans from Erythrina burana.

Bioactivity-directed fractionation of the CHCl3 extract of the bark of Erythrina burana afforded phaseollidin [1] and cristacarpin [2]. Both 1 and 2 exhibited moderate but selective activity towards DNA repair-deficient yeast mutants, whereas only 1 was found to be cytotoxic. 13C-nmr spectra of both compounds were assigned.

Animals↗