Pancytopenia after removal of copper from total parenteral nutrition

Patients who develop cholestatic jaundice during chronic total parenteral nutrition (TPN) can develop significant hematologic complications due to hypocupremia if copper supplementation is withheld. A 36-year-old female with short bowel syndrome developed progressive liver dysfunction 6 months after initiation of TPN. Trace elements were omitted from her TPN because of cholestasis and persistent hyperbilirubinemia. Despite chronic diarrhea, absorption of some dietary copper was anticipated from her oral diet. Fifteen months later, the patient became red cell transfusion dependent, and her neutrophil and platelet counts steadily declined. After 19 months of receiving TPN without trace elements, her serum copper level was 25 microLg/dL (normal: 70 to 155 microg/dL). Provision of trace elements for 2 months was associated with increased serum copper, neutrophil and platelet counts and independence from red cell transfusions. When the serum copper level reached 186 microg/dL, copper supplementation was discontinued. Over the next 3 months, serum copper level fell to 10 microg/dL, neutrophil and platelet counts fell precipitously, and red cell transfusions were resumed. Once again, copper, neutrophil and platelet levels promptly rebounded with parenteral copper supplementation. Although anemia and neutropenia are well-recognized hematologic consequences of copper deficiency, thrombocytopenia rarely has been reported. This is the first report of pancytopenia secondary to TPN-related copper deficiency in which the association was confirmed when hypocupremia recurred.

beta-adrenergic receptor/cAMP-mediated signaling and apoptosis of S49 lymphoma cells

beta-Adrenergic receptor (betaAR) activation and/or increases in cAMP regulate growth and proliferation of a variety of cells and, in some cells, promote cell death. In the current studies we addressed the mechanism of this growth reduction by examining betaAR-mediated effects in the murine T-lymphoma cell line S49. Wild-type S49 cells, derived from immature thymocytes (CD4(+)/CD8(+)) undergo growth arrest and subsequent death when treated with agents that increase cAMP levels (e.g., betaAR agonists, 8-bromo-cAMP, cholera toxin, forskolin). Morphological and biochemical criteria indicate that this cell death is a result of apoptosis. In cyc(-) and kin(-) S49 cells, which lack G(s)alpha and functional protein kinase A (PKA), respectively, betaAR activation of G(s)alpha and cAMP action via PKA are critical steps in this apoptotic pathway. S49 cells that overexpress Bcl-2 are resistant to cAMP-induced apoptosis. We conclude that betaAR activation induces apoptosis in immature T lymphocytes via G(s)alpha and PKA, while overexpression of Bcl-2 prevents cell death. betaAR/cAMP/PKA-mediated apoptosis may provide a means to control proliferation of immature T cells in vivo.

Beta2-adrenergic receptor polymorphisms at codon 16, cardiovascular phenotypes and essential hypertension in whites and African Americans

Beta2-adrenergic receptors (beta2-AR) contribute to cardiovascular regulation by influencing several functions and previous studies suggest that a decreased function of the beta2-AR may be involved in essential hypertension. Beta2-AR are polymorphic and certain polymorphisms of these receptors are of functional importance. We focus here on the Arg16-->Gly16 beta2-AR polymorphism, which shows enhanced agonist-promoted downregulation of the receptor and which, in two recent studies, yielded opposite results in terms of association with essential hypertension: an increased frequency of the Gly16 variant in African-Caribbean hypertensives and of the Arg16 variant in offspring of Norwegian white hypertensive parents. In the current study, we genotyped 243 subjects, including both African-American and white individuals, for codon 16 polymorphism and assessed blood pressure and cardiovascular function using impedance cardiography and pressor sensitivity to phenylephrine. We found similar patterns of cardiovascular function and expression of hypertension with the two genotypes of codon 16. There was no statistically significant difference in the overall allelic distribution of the two genotypes: among African-Americans, 51% of the hypertensives and 50% of the normotensives carried the Arg16 allele, whereas among the white subjects 40% of the hypertensives and 47% of the normotensives were carriers of the Arg16 allele. Although we observed a statistically significant increase in the Arg16/Gly16 heterozygotes in the African-American population, the Gly16 allele was not significantly increased in the African-Americans compared to whites. These findings indicate that the codon 16 polymorphisms are not associated with hypertension in a mixed American study population nor do they appear to substantially impact on a variety of hemodynamic variables.

Comparative pharmacodynamics and pharmacokinetics of candesartan and losartan in man

The angiotensin II antagonistic effects of candesartan and losartan were compared in-vivo after single and repeated doses. Effects were related to antagonistic activity in plasma. In this double-blind, crossover study, 12 healthy male volunteers received, in random order, daily oral doses of 8 mg candesartan cilexetil or 50 mg losartan for seven days. On day 1 and day 8, dynamics and kinetics were assessed up to 48 h after dosing. Antagonistic effect was determined from the antagonist-induced rightward shifts of the diastolic blood pressure response curves to exogenously administered angiotensin II measured as the dose ratio (DR). The antagonistic activity in plasma was measured using an ex-vivo/in-vitro radioreceptor assay. Specific high-performance liquid chromatography assays determined plasma concentrations of candesartan, losartan and its active metabolite EXP-3174. The pharmacokinetic properties of candesartan and losartan were comparable and antagonistic activity in plasma almost identical (ratio candesartan: losartan = 0.97 and 1-2 after single and multiple doses, respectively). However, the antagonistic effects of candesartan and losartan in-vivo were quite different. Twenty-four hours after single dosing with candesartan a clinically relevant rightward shift in the angiotensin II dose-response curve (DR= 3.2) occurred that was more pronounced than that following losartan administration (DR=2.1, ratio candesartan: losartan= 1.65). Twenty-four hours after multiple doses of candesartan or losartan, the values of the DR were 4.8 and 2.3, respectively (ratio candesartan: losartan = 1.94). The values of DR for candesartan were significantly higher compared with losartan between 6 and 36h after a single dose and between 3 and 24 h post-dose following multiple dose administration. A counter-clockwise hysteresis was apparent between antagonistic activity in plasma and antagonistic effect. Despite equivalent angiotensin II antagonistic activity in plasma, the pharmacodynamic effect of candesartan cilexetil was greater than that of losartan. Candesartan appeared to have a slower off-rate from the angiotensin AT1-receptor compared with losartan, nevertheless differences in distributional phenomena or the extent of insurmountable antagonistic activity cannot be ruled out.

Variability in phenylephrine response and essential hypertension: a search for human alpha(1B)-adrenergic receptor polymorphisms

Genetic polymorphisms in drug receptors, in particular adrenergic receptors, may contribute to intersubject differences in pharmacologic response. We tested patients and first-degree normotensive and hypertensive relatives of patients with essential hypertension and found substantial intersubject variability in blood pressure response to infusion of the alpha(1)-adrenergic agonist phenylephrine. Because response to phenylephrine depends upon interaction with alpha(1B)-adrenergic receptors, we tested whether polymorphisms in this receptor contribute to the variable responses. Accordingly, we developed a polymerase chain reaction-based method, generating four exon-spanning fragments, to identify polymorphisms in the coding sequence of the two exons of the human alpha(1B)-adrenergic receptor. We sequenced the entire coding sequence of exon 1 from 51 subjects and exon 2 from 16 of these 51 subjects. Compared with the published sequence for the alpha(1B)-adrenergic receptor, we found one amino acid addition in exon 2 at position 368 (Arg) and one substitution (Arg371Gly) in all subjects. We thus suggest we have defined the correct coding sequence of the human alpha(1B) receptor. We found two "silent" polymorphisms in exon 1, one of which occurred in 3 of 51 subjects. These polymorphisms were unrelated to blood pressure status or response to phenylephrine. The 95% confidence intervals for expression of polymorphisms in exons 1 and 2 were 0 to 11%. Our data reveal that although phenylephrine response varies in humans, frequent polymorphisms in the coding sequence of the human alpha(1B)-adrenergic receptor appear not to account for this variation or for the increased blood pressure in patients with essential hypertension.

PCR-based methods for identifying genetic variations in human alpha1B- and beta2-adrenergic receptors

alpha- and beta-adrenergic receptors belong to the superfamily of G-protein-coupled, seven transmembrane domain receptors and regulate a variety of cellular processes. Previous studies have demonstrated that changes in the amino acid sequence can result in substantial changes in the function of the receptors and it has been suggested that there may be an association between different disease states and the altered structure of alpha- and beta-adrenergic receptors. Accordingly, we have developed a simple PCR method for the identification of polymorphisms in the coding sequences of the human beta2-adrenergic receptor and the alpha1B-adrenergic receptor. This method may be useful for screening individual patients or at-risk populations for endocrine-metabolic disorders, as well as for asthma, cardiovascular disorders, and neuropsychiatric diseases.

Angiotensin II antagonism and plasma radioreceptor-kinetics of candesartan in man

AIMS

The pharmacodynamic properties of the angiotensin II antagonist candesartan in humans were assessed from the rightward shifts of angiotensin II dose-effect curves (Schild regression technique). The pharmacokinetic characteristics were determined by radioreceptor assay (r.r.a.) and h.p.l.c.

METHODS

Twelve healthy male volunteers received single oral doses of 4, 8 and 16 mg candesartan cilexetil and placebo. Plasma was obtained for h.p.l.c. and r.r.a. (receptors: rat lung; radioligand: [125I-Sar1Ile8]-angiotensin II). Before and up to 24 h post dosing angiotensin II was infused in ascending dose steps until blood pressure (systolic and/or diastolic) increased by +25 mmHg. Individual angiotensin II dose-effect curves were fitted according to an Emax model and dose ratios (DR) calculated from the antagonist induced rightward shifts.

RESULTS

Candesartan, the active metabolite of candesartan cilexetil, declined from peak concentrations at about 4 h with a t1/2 of about 6 h. A linear relation (slope 1) between h.p.l.c. and r.r.a. data revealed that there is no other active metabolite. DR at 6-9 h post dosing reached a maximum of about 30 and at 24 h still amounted to 4-7, indicating the persistence of a relevant antagonistic effect in vivo. The apparent Ki-doses (derived from Schild regression plots) indicated a high potency (1.9 mg at 24 h) and slow decline of effect. Between plasma concentrations and antagonistic effect a counterclockwise hysteresis was visible.

CONCLUSIONS

A longer persistence of the antagonistic effect at the receptor site than expected by the presence in plasma indicates a slow off-rate of candesartan cilexetil from in vivo receptors. This provides an additional rationale for the observed 24 h therapeutic activity of candesartan cilexetil.

Pharmacodynamic and pharmacokinetic properties of an angiotensin II receptor antagonist--characterization by use of Schild regression technique in man

OBJECTIVE

The pharmacodynamic properties of a new angiotensin II receptor antagonist (BAY 10-6734) in humans were to be quantitatively characterized from the rightward shifts of the agonist dose-response curves after administration of different doses of the antagonist.

METHODS

24 healthy male volunteers received single oral doses of 20-300 mg BAY 10-6734. Before and up to 23 h post dosing (p.d.) plasma was obtained for HPLC measurement of parent compound and active metabolite BAY 10-6735. Exogenous angiotensin II was infused in increasing dose steps until blood pressure had increased by +25 mmHg. Angiotensin II dose-response curves were fitted individually using the sigmoidal Emax model. From the antagonist-induced rightward shifts, as compared to a premedication curve, dose ratios (DR) were determined and DR-1 plotted versus applied dosages and measured plasma concentrations. From these Schild regression plots the fictive doses and concentration (Ki) inducing a DR-1 = 1, i.e. a 2-fold shift in agonist dose-response curves, were derived. The "doubling (t2.0) time" of the apparent Ki doses was calculated.

RESULTS

BAY 10-6734 dose-dependently induced rightward shifts of the angiotensin II blood pressure response curves, mean maximum DR at 2 h p.d. ranged from 42 (80 mg) to 216 (300 mg), and at 23 h p.d. decreased to about 2 (80 mg) to 4 (300 mg). Pharmacodynamic (3.4-4.6 h) and pharmacokinetic half-lives (3.4-4.3 h) were nearly identical. Apparent Ki doses increased from about 1-2 mg at 2 h p.d. to about 80-100 mg at 23 h p.d., their time course revealed a doubling (t2.0) time of 3.5-3.8 h. A Ki concentration of about 10 micrograms/l was obtained for the active metabolite BAY 10-6735.

CONCLUSIONS

Oral administration of BAY 10-6734 in man antagonized angiotensin II dose blood pressure response curves in a dose-dependent manner. The time kinetics of the pharmacodynamic effect, derived from the decay of DR-1 values, as well as the doubling time of the apparent Ki values well agreed with the pharmacokinetic half-life. Schild regression revealed competitive angiotensin II antagonistic properties within the dose/concentration range tested. This technique was shown to be an adequate means to evaluate pharmacodynamic potency and kinetic behavior of an angiotensin II receptor antagonist in vivo.

Repeated lipoinjections for stress urinary incontinence

A total of 30 women with stress incontinence underwent periurethral injection of autologous fat under spinal anesthesia. The fat was harvested from the abdominal wall by liposuction. Preoperative evaluation consisted of history, physical examination, and urodynamic evaluation. For study purposes, some patients also underwent bladder and urethral ultrasonography and magnetic resonance imaging studies. The first 13 patients received a single periurethral lipoinjection, and the following 17 patients received sequential injections when needed at 3-month intervals. Results were assessed by subjective questionnaire performed at 3 and 12 months. All patients had intrinsic sphincteric deficiency. Of the first group, there were only four patients (31%) cured after 1 year of follow-up. On the other hand, in the group that received repeated injections, there were 11 patients (64%) cured with a mean of two injections at 1-year follow-up. Our results show that this procedure warrants continued clinical investigation because it may be useful in selected cases of urinary stress incontinence.

Evidence that a 16-kilodalton integral membrane protein antigen from Schistosoma japonicum adult worms is a type A2 phospholipase

Type A2 phospholipase (PLA2) activity has been observed in integral membrane protein extracts of Schistosoma japonicum. Antiserum raised against bee venom PLA2 recognized a single 16-kDa band in the parasite extracts; it also localized to antigen in the gut lining of fixed adult schistosomes as shown by immunofluorescence techniques. Evidence was obtained that the molecule was expressed at low levels in comparison with other integral membrane proteins and was weakly immunogenic in rabbits. Two oligonucleotide probes were constructed on the basis of highly conserved regions between the nucleotide sequences of rat, bovine, rattlesnake, and bee venom PLA2; these probes were used to isolate S. japonicum genomic DNA phage clones. A 1.8-kb FnuD2 fragment was shown by Southern blot analysis to strongly hybridize with the 5' 32P-labeled PLA2 oligonucleotides in both S. japonicum genomic DNA and DNA from one of the phage clones. The nucleotide and predicted amino acid sequences of this fragment revealed homology with the C terminus of PLA2s from different species.

Outpatient dobutamine for end-stage congestive heart failure

Eleven patients with refractory class IV congestive heart failure who were not candidates for cardiac transplantation were given iv dobutamine therapy on an outpatient basis. All patients underwent hemodynamic evaluation to confirm a beneficial response to low dose (5 micrograms/kg.min) dobutamine and to establish arrhythmia control both on and off dobutamine before hospital discharge. Six of the 11 patients could not be weaned from dobutamine in hospital and were discharged on continuous infusion (maximum dose, 5 micrograms/kg.min), while four were discharged with an infusion regimen ranging from 3 to 5 consecutive days/wk. All patients had a chronic venous access placed and were instructed on the use of an external battery-powered infusion pump with a container holding a concentrated solution of dobutamine hydrochloride. All infusions were delivered at home on an ambulatory basis. Intravenous drug support was discontinued gradually over an average of 3.2 months; seven of 11 patients were able to be weaned entirely from iv inotropic therapy and were maintained on oral therapy alone. Seven of the 11 patients (six of whom were maintained on oral therapy alone) required no hospital readmission during the infusion or follow-up period.

[Animal experiment and biopsy studies on the cause, manifestations and diagnostic relevance of perifascicular muscle fiber atrophy]

On the basis of previous (n = 23) and current muscle biopsies (n = 25) as well as five animal-experimental investigations, the paper deals with the cause and the manifestation of perifascicular muscle-fiber atrophy. A deteriorated trophic situation of the subfascial or marginal muscle fibers in patients suffering from immunocomplex vasculopathies in connection with a reduced supply of blood to the muscles is seen as the cause of the areactive weight loss (atrophy). This is accompanied by a considerably reduced capillary supply of blood to the muscle fibers. Even in normal conditions, the portion of collateral vessels and capillaries is lower in the subfascial region than in the center of the fascicle. When the blood supply is disturbed, the marginal fibers are in a trophic situation worse than that of the central muscle fibers. They become atrophied. In responsive patients, the muscle fibers regenerate and recapillarize during the convalescence period. This can be shown histochemically by means of the alkaline phosphatase reaction. The extent of perifascicular musclefiber atrophy can be fixed in quantitative terms by the method of Baumli and Mumenthaler. Where a second biopsy is indicated, results can be obtained regarding the changes in the perifascicular atrophy as a consequence of the therapy provided.

[Problem of diagnostic muscle tissue removal: biopsy, preparation and preservation]

Intensive professional cooperation of all diagnostical branches needed incl. surgery is presupposition for the investigation of muscle biopsies. Knowledge needed on diagnostic clearing in advance and correct determination of kinds of biopsy as well as careful detraumatic taking of tela have decisive influence on the statement value of the result of investigation techniques concerning fine-tela. Muscle biopsies should be made exclusively at such places where the technical basis is available for optimum investigation and preparation.

[Clinically significant histologic, histochemical and morphometric parameters in the evaluation of muscle biopsies]

Many of the diagnostic advances in the field of myopathies have been achieved by the examination of samples of muscle removed by biopsy. A muscle selected for biopsy must be obtained atraumatically with the fibres orientated longitudinally. Artefacts are avoided by freezing the sample in liquid nitrogen. The typing of muscle fibres by using the ATPase and dehydrogenase reactions is of advantage to the interpretation of muscle diseases. An accurate method for the determination of changes in the size of muscle fibres is a must. The construction of histograms, standard values for mean fibre diameters, the estimation of the proportion of various types of fibres, variability coefficient, atrophy and hypertrophy factors are a help. A few studies have been performed concerning the effect of a physical therapy on the composition of the fibres of skeletal muscles. A more differentiated physiotherapeutic treatment based on the histochemical and morphometrical results of the muscle biopsy is essential for the therapy of the myopathies.

Evaluation of intragastric pH in acutely ill patients

The effect of various modalities on maintaining a high intragastric pH in acutely ill patients was evaluated. Twelve patients with one or more organ system failures had the effect of nasogastric suction, intragastric antacid instillation, and intravenous cimetidine administration on intragastric pH determined by an indwelling, intragastric pH probe. Each therapeutic modality was administered for 12 hours and the order of performance randomized. Nasogastric suction was associated with a constant intragastric pH of less than 2.0. Mean intragastric pH with cimetidine administration was significantly higher than with antacid administration and consistently greater than 5.0. If low intragastric pH represents susceptibility to acute mucosal lesions, cimetidine therapy was more effective than antacids in the doses and frequency of administration used in this study in maintaining a high intragastric pH, and it may be effective in preventing stress ulcer formation.

[Activity alterations of unspecific esterases during wound healing. Investigations by means of electrofocusing (author's transl)]

Electrofocusing of skin-wound extracts on polyacrylamide flat gels is appropriate for zymographic separation of the esterase isoenzymes. In animal experiments and corpse material most fractions indicated non-synchronous, wound-age depending alterations of activity. As early as 15 minutes after incision obvious activity increases of A1-3-isoenzymes could be demonstrated, followed by a transitory decrease and another maximum. Important activities of the A4-isoenzymes became evident not before the 1st (human) resp. 3rd hour (guinea pig) after incision. There are no sufficient correlations between activity alterations and wound age, to allow a fairly exact time interval classification.