Superior vena cava and right atrium wall infective endocarditis in patients receiving hemodialysis

Infective endocarditis is significantly more common and causes greater morbidity and mortality in patients receiving hemodialysis than in the general population. Episodes of bacteremia during hemodialysis are primarily the result of frequent vascular access through an arteriovenous fistula, a vascular graft, or an indwelling vascular catheter. This leads to dialysis access infection and secondary bacteremia. We describe 4 cases of patients receiving hemodialysis, with an indwelling intravascular dialysis catheter, who developed right-sided endocarditis with vegetations located exclusively on the superior vena cava and right atrium wall. All patients had persistent bacteremia with Staphylococcus, secondary to an indwelling intravascular hemodialysis catheter, which led to seeding of the right-sided cardiac wall, causing infective endocarditis. The rates of acceptance for hemodialysis are increasing, along with improved survival in this group of patients. This will probably lead to an increase in the incidence of infective endocarditis, with atypical presentations such as superior vena cava and right-sided cardiac wall endocarditis.     

A new function for the serine protease HtrA2 in controlling radiation‐induced senescence in cancer cells

Radiation therapy can induce cellular senescence in cancer cells, leading to short‐term tumor growth arrest but increased long‐term recurrence. To better understand the molecular mechanisms involved, we developed a model of radiation‐induced senescence in cultured cancer cells. The irradiated cells exhibited a typical senescent phenotype, including upregulation of p53 and its main target, p21, followed by a sustained reduction in cellular proliferation, changes in cell size and cytoskeleton organization, and senescence‐associated beta‐galactosidase activity. Mass spectrometry‐based proteomic profiling of the senescent cells indicated downregulation of proteins involved in cell cycle progression and DNA repair, and upregulation of proteins associated with malignancy. A functional siRNA screen using a cell death‐related library identified mitochondrial serine protease HtrA2 as being necessary for sustained growth arrest of the senescent cells. In search of direct HtrA2 substrates following radiation, we determined that HtrA2 cleaves the intermediate filament protein vimentin, affecting its cytoplasmic organization. Ectopic expression of active cytosolic HtrA2 resulted in similar changes to vimentin filament assembly. Thus, HtrA2 is involved in the cytoskeletal reorganization that accompanies radiation‐induced senescence and the continuous maintenance of proliferation arrest.     

Clinical significance of slow paroxysmal atrial tachycardia

This study examines the clinical setting, characteristics, and follow-up of 173 patients who had slow paroxysmal atrial tachycardia (SPAT) (> 4 beats, rate < 150 bpm) during 24-hour Holter monitoring. These episodes were classified by probable mechanism according to recognized ECG criteria and included AV nodal reentry (AVNR), sinoatrial nodal reentry (SANR), and automatic (A). There were 76 males (44%) with a mean age of 72 years and 97 females (56%) with a mean age of 73 years. The indications for Holter recording revealed that the SANR and A subgroups had a higher frequency of cerebral symptoms compared to AVNR (p < 0.01). Chest pain was more common in the SANR group as compared to the other two groups (p < 0.01). There was no difference in the frequency of palpitation in the three subgroups. The mean rate of SPAT for the entire groups was 115.2 ± 14 and these episodes had a mean duration of 5.58 ± 3.07 seconds. The SANR subgroup had a significantly slower rate (107.1 ± 9.2) as compared to the AVNR subgroup (p < 0.01). One hundred fourteen patients were available for follow-up. The average period of follow-up was similar for all three groups. At follow-up the frequency of sick sinus syndrome as determined clinically and permanent pacemaker insertion was significantly greater in the SANR subgroup (p < 0.01) as compared to the other subgroups which did not differ from each other.     

Phosphorus burn in primates: a conclusive experimental study of a new specific therapy

A conclusive biochemical and histopathological study was carried out on primates being given a phosphorus burn. This was performed in order to test and confirm the non-toxicity of our recently suggested specific treatment for phosphorus burns. Two primates were exposed to an experimental phosphorus burn, the first received the burn only, while the second was treated after the burn. The first animal was killed 5 days after sustaining the burn because of its severe condition; the second animal survived. Biochemical studies of blood and urine samples from both primates taken during the experiment showed marked changes in kidney and liver function, disturbed electrolyte balance and a high incorporation of phosphorus ions into the blood of the first primate. The corresponding values in the surviving primate were normal and no incorporation of phosphorus or copper ions into the blood was observed. The histopathological studies on the dead monkey confirmed the biochemical observations and suggested severe morphological aberration in the kidney, liver, spleen and heart. This cardinal experiment follows up many previous investigations in phosphorus-burned rats. It seems that the suggested therapy alleviates the effects of phosphorus burns and is non-toxic to primates.     

Free amino acids in the cytosol of human atrium and ventricle of the heart, as analyzed by gas-liquid chromatography

Size and composition of the amino acid pool in the cell cytosol of atrial and ventricular heart muscle of 6-8 week old human embryos was evaluated by gas-liquid chromatography. It was found that the free amino acid pool in the ventricular heart muscle is about 50% higher than in the atrium. Arginine constituted the most abundant amino acid in the ventricular and atrial heart muscle as well. Glutamic acid and alanine were the next most common amino acids and represented 10-18% and 7-10% of the amino acid pools, respectively. After appropriate biotransformation, these amino acids may not only be important substrates for the energy cycles of the heart, but may also play a critical role as stimulators of mitosis and regulators of the synthesis of nucleic acids and proteins.     

Controlled release of radioprotective agents from matrix tablets--effect of preparative conditions on release rates

Release rates of radioprotective agents from insoluble matrix tablets were measured as a function of ethylcellulose/stearic acid ratio and active ingredient concentration in the matrix. The influence of the compacting pressure applied during tablet formation on the release of these aminothiol compounds was also examined. The kinetic data conformed with the Higuchi square root equation and first order release. As both plots were linearly acceptable, a statistical method for release mechanism identification using the kinetic experimental results obtained without any further transformation was used. This non-linear regression search procedure accompanied by the chi 2-square test has shown that that aminothiol release from the matrix tablets definitely follows the Higuchi square root equation. Increasing the ethylcellulose amount in the matrix consequently improves the degree of wettability and leads to a faster rate of solvent penetration. This tends to release the aminothiols more rapidly from the matrix tablets. Solvent penetration, which also follows a square root of time relationship, is probably the rate-limiting factor in the release process. The linear increase in release rates of the aminothiols observed with ethylcellulose concentration is explained by a parallel increase in the porosity of the matrix tablets. Increase in the drug concentration in the tablet increases the cysteine hydrochloride release rate and decreases the cysteamine hydrochloride release rate. A similar effect was also observed by applying increasing compacting pressure during matrix tablet formation. It was suggested that these two experimental factors differently affect the internal structure of the matrix during the preparation process.(ABSTRACT TRUNCATED AT 250 WORDS)     

Demographic evaluation of successful antipsoriatic climatotherapy at the Dead Sea (Israel) DMZ Clinic

Background Natural balneologic properties, thermomineral springs and unequivocal success in improving psoriasis, attract an ever-growing number of psoriatlcs to the DMZ Clinic on the shores of the Dead Sea in Israel. Methods This paper analyses the rate of success of this balneotherapy in 740 psoriatics who flew in from Germany specifically for this treatment, during 1995, as a function of sex, family history of the disease, number of previous treatments at the Dead Sea, skin type, skin involvement, joint involvement, duration of treatment, sun-exposure schedule, remission length, and psychologic supervision. Results After 4 weeks, 70% of the patients were completely cleared, this improvement being about the same across both sexes. Family history of the disease, skin type, and psychologic support did not affect the rate of success. On the other hand, previous treatments at the Dead Sea, moderate to severe skin surface involvement, and participation of arthritis, improved the chance of better clearing of the psoriatic condition. Similar improvement was obtained by a longer sun-exposure schedule and a complete 4-week treatment. Conclusion These results indicate that the medical improvement in the psoriatic condition after a 4-week stay at the Dead Sea can be better enhanced and its remission prolonged if additional demographic and anamnestic factors are carefully taken into account.