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Biomedical subjects

M Kessler

Publications and source records attributed to M Kessler.

At least 325 records · Page 18Linked to original sources
PubMed1988

Constant-pressure perfusion on the isolated rat liver: local oxygen supply and metabolic function.

Isolated rat livers were perfused with a haemoglobin-free Krebs-Ringer solution containing 35 g albumin/1. During a 3 hour perfusion total flow, O2-uptake rate and local O2-supply remained constant. During the same period of time the ATP-content increased from a value of 0.59 +/- 0.17 mumol/g to 1.81 +/- 0.42 mumol/g. The low initial value was due to the ischaemic period during preparation of the organ. The glycogen content increased by 13.4 mg/g, indicating that the organ did not lose the ability for glyconeogenesis. In addition to an increase in glycogen, there was a continuous increase in the glucose concentration of the perfusate, while lactate was taken up by the organ. The results indicate that the isolated organ can be perfused for at least 3 hours without development of disturbances in local O2-supply.

Adenosine Triphosphate↗
PubMed1987

Use of cystine to distinguish glutamate binding from glutamate sequestration.

Cystine is shown to be a high-affinity substrate for the chloride-dependent glutamate exchange system in brain membranes, which mediates what has previously been considered chloride-dependent glutamate 'binding'. Similarities in the pharmacological profile and in kinetic properties suggest that this transport system may be a high-affinity adaptation of the transport system xc- present in somatic cells. Since cystine selectively inhibits glutamate sequestration and does not interact with the major glutamate binding sites, it can be used to assess the contribution of sequestration to overall 'binding' of glutamate or glutamate-analogs or to suppress sequestration in receptor binding assays. As an example, it is shown that more than 90% of 'bound' [3H]aminophosphonobutyrate [( 3H]APB) is displaced by cystine and should be interpreted as APB sequestration.

Animals↗
PubMed1987

Human RNA polymerase II can prematurely terminate transcription of the adenovirus type 2 late transcription unit at a precise site that resembles a prokaryotic termination signal.

Premature termination of transcription has been demonstrated by eukaryotic RNA polymerase II at specific sites in the major late transcriptional unit of SV40 and in one of the transcriptional units of the parvovirus, minute virus of mice (MVM) (Y. Aloni and N. Hay, CRC Critical Reviews of Biochem., 18:327-383, 1985). In both cases the prematurely terminated (attenuated) RNA can be folded into a hairpin structure followed by U-residues that resemble a termination signal in prokaryotes. The experiments presented herein demonstrate premature termination of transcription 185 nucleotides (nt) downstream from the major late promoter of adenovirus type 2 (Ad2) in vivo, and in vitro in isolated nuclei and in HeLa whole cell extract. As in SV40 and MVM the attenuated RNA of Ad2 can be folded into a hairpin structure followed by U-residues. Transcription-termination was significantly reduced when ITP replaced GTP and when Br-UTP replaced UTP in the transcription reaction mixture, indicating that RNA secondary structure and the rU-dA interactions, respectively, are parts of the termination signal. Moreover, in isolated nuclei transcription-termination at the attenuation site occurred when the reaction mixture contained between 50-150 mM NaCl but not when it contained 300 mM NaCl. These results indicate that, at least in isolated nuclei, attenuation can be regulated. The possible involvement of termination factor(s) in the regulation of attenuation is discussed.

Adenoviridae↗
PubMed1987

Primary renal lymphoma presenting as acute renal failure.

Diffuse bilateral infiltration of the kidneys by lymphoma cells is a rare but well-documented cause of acute renal failure (ARF). Only 51 such cases have been reported, 15 of which had ARF as the initial presentation of lymphoma. The clinical and pathologic features of these 15 cases and of two additional cases reported herein are reviewed. The diagnosis should be suspected in a patient with ARF, bilateral enlargement of the kidneys, minimal proteinuria, nonspecific findings on urinalysis, and absence of features of allergic tubulointerstitial nephritis. Renal imaging techniques may suggest the possibility of lymphomatous infiltration, but only renal biopsy or autopsy can provide a definitive diagnosis. Although modern chemotherapy and/or radiation therapy usually leads to a dramatic normalization of renal function, almost all patients eventually die of widespread recurrent lymphoma, despite the absence of clinical or pathologic involvement of the kidneys at the time of death.

Acute Kidney Injury↗
PubMed1987

Cerebrocortical microcirculation in different stages of hypoxic hypoxia.

This study investigated the relation between local cerebrocortical oxygen tension (PO2) and cerebrocortical microflow (CMF) during normoxia (FiO2 = 0.3) and hypoxic hypoxemia (FiO2 = 0.16 and 0.1). Measurements were performed on mechanically ventilated rats and rabbits anesthetized with 0.8% Ethrane and maintained within normocapnic limits. Polarographic techniques based on the use of multiwire surface electrodes were applied for measurements of local PO2 and CMF. In both species the mean tissue PO2 values were similar under normoxia (26.0 and 31.5 mm Hg for rats and rabbits, respectively). CMF histograms showed pronounced heterogeneity. The highest CMF values exceeded the lowest ones by a factor of 36 in the rat and by a factor of 26 in the rabbit. Mean CMF values were 6.67 +/- 0.72 and 4.09 +/- 0.14 relative units (for definition see text) in rats and rabbits, respectively. During hypoxemia, if the mean tissue PO2 was greater than 5 mm Hg, mean CMF did not change but a change in the pattern of microflow distribution was observed with increases in some CMF values (up to 670% of control) and decreases in others (down to 12% of control). When mean tissue PO2 values of less than 5 mm Hg were observed during hypoxemia, mean CMF increased in both species by approximately 50% on average. The increase in CMF could be seen in each individual CMF recording. We conclude that in the brain cortex local regulatory mechanisms are responsible for the change in the pattern of distribution of microcirculation during moderate tissue hypoxia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

L-phenylalanyl-L-glutamate-stimulated, chloride-dependent glutamate binding represents glutamate sequestration mediated by an exchange system.

Stimulation of glutamate binding by the dipeptide L-phenylalanyl-L-glutamate (Phe-Glu) was inhibited by the peptidase inhibitor bestatin, suggesting that the stimulation was caused by glutamate liberated from the dipeptide and not by the dipeptide itself. It further suggests that this form of glutamate binding should be reinterpreted as glutamate sequestration and that stimulation of binding both by dipeptides and after preincubation with high concentrations of glutamate is likely to be due to counterflow accumulation. Several other criteria indicate that most of glutamate binding stimulated by chloride represents glutamate sequestration: Binding is reduced when the osmolarity of the incubation medium is increased, when membranes incubated with [3H]glutamate are lysed before filtration, and when membranes are made permeable by transient exposure to saponin. Moreover, dissociation of bound glutamate after a 100-fold dilution of the incubation medium is accelerated about 50 times by the addition of glutamate to the dilution medium. This result would be anomalous if glutamate were bound to a receptor site; it suggests instead that glutamate is transported in and out of membrane vesicles by a transport system that preferentially mediates exchange between internal and external glutamate. Glutamate binding contains a component of glutamate sequestration even when measured in the absence of chloride. Sequestration is adequately abolished only after treating membranes with detergents; even extensive lysis, sonication, and freezing/thawing may be insufficient.

Aminopeptidases↗
PubMed1987

[Is enoxaparine (PK 10169) a good anticoagulant in chronic hemodialysis?].

Tolerance and efficacy of single i. v. injections of PK 10169 (1 mg/kg) during installation were evaluated in 10 patients with stable chronic renal insufficiency treated with 3 sessions of hemodialysis weekly (sessions of 4 and 5 hours). Tolerance was good in all cases. Efficacy was globally satisfactory (no complete coagulation) but by the 4th hour in 7 out of 30 sessions coagulation was apparent in the bubble trap with elevation of residual blood volume, recurring in the same patient but not affecting result of dialysis. In these cases anti-Xa activity was reduced from the 2nd hour and at end of dialysis, with a markedly elevated FPA level. For most patients it is possible to envisage 5-hour sessions, but in those few susceptible to develop coagulation repeated clinical surveillance of all circuit elements is necessary.

Adult↗
PubMed1986

[Class I alloantigens in alopecia areata].

HLA-ABC antigens in 51 patients suffering from alopecia areata have been analyzed by means of 47 different antigens using the microlymphocytotoxicity test. In comparison with various control populations, there could not be proved any significant association in the tested antigens. Thus we suggest that the reported associations may have been caused by geographical or racial variations.

Alopecia Areata↗