Thrombotic thrombocytopenic purpura associated with ticlopidine therapy

A patient who developed thrombotic microangiopathy while on ticlopidine therapy is reported. Thrombotic microangiopathy resolved with discontinuation of the drug and treatment with plasma exchange and has not recurred during 10 months of follow-up. The emerging data on the risk of developing thrombotic microangiopathy while on Ticlopidine and the possible mechanisms underlying this association are reviewed. The need for careful monitoring of the platelet count and hematocrit in addition to the white cell count during the first 3 months of therapy with this drug is emphasized. It is important that nephrologists, who are frequently called upon to diagnose thrombotic microangiopathy, be aware of its association with ticlopidine. Other drug-induced syndromes of thrombotic microangiography are also considered and compared, with respect to possible mechanisms of disease in each case.

The European Sero-Epidemiology Network

The purpose of serological surveillance is to monitor levels of immunity to particular diseases within a population in order to enhance the quality of information on which public health measures, such as vaccination programmes, are based. Serological surv

Evaluation of diaphragm electromyogram contamination during progressive inspiratory maneuvers in humans

The diaphragm electromyogram (EMGdi) is susceptible to contamination by non-diaphragm related electrical signals such as the ECG, electrode motion artifacts, and other sources of noise. It is difficult to distinguish between these contaminating signals and those that are representative of the non-contaminated EMGdi, especially during periods when the EMGdi amplitude is relatively small, as during mild contractions of the diaphragm. The aim of the present study was to evaluate how contaminating signals influence the EMGdi power spectrum center frequency (CF) during progressive inspiratory maneuvers. EMGdi and transdiaphragmatic pressure (Pdi) were measured via an esophageal electrode in eight patients with cervical cord injury performing inspiratory capacity (IC) maneuvers. The influence of the contaminating sources on CF was evaluated by two spectral deformation indices, one which is sensitive to both high and low frequency spectral deformation (omega index), and the other which is sensitive to high frequency deformation only (CF1000/CF500 index). The results indicated that EMGdi CF values scattered over a wide frequency range, particularly when the signals were obtained at Pdi levels less than 15% of Pdimax, or at lung volumes less than 30% of IC. When the spectral deformation indices were applied, the scattering in CF values was drastically reduced. This was expressed by a factor of 4 reduction in the coefficient of variation of the CF values. The majority of the excluded EMGdi signals (i.e. not satisfying the spectral deformation index inclusion levels), had low CF values mainly due to the presence of electrode motion artifacts. It was concluded that: 1) The majority of EMGdi power spectrums are deformed early on during unloaded inspirations, and their CF values should be carefully interpreted as being representative of diaphragm function. 2) The relative contribution of contaminating signals in the EMGdi decreases proportionally throughout the first two thirds of an inspiration to IC. 3) The use of visual inspection of the signal in the time domain is questionable as a method to discriminate non-contaminated signals. 4) Analysis of the signal in the frequency domain makes it possible to detect the influence of signal contamination.

Effects of social housing condition on the response of the Shionogi mouse mammary carcinoma (SC115) to chemotherapy

In the present study, we demonstrate that social housing conditions significantly alter the response of the transplantable androgen-responsive Shionogi mouse mammary tumor (SC115) to chemotherapy. Mice were reared either in groups (G) or as individuals (I). Immediately following tumor cell or vehicle injection, mice were rehoused from group to individual (GI) or from individual to group (IG) conditions. A combination of Adriamycin (4 mg/kg) and cyclophosphamide (61.5 mg/kg), in a series of three i.p. injections 7 days apart, was initiated when mean tumor weights of mice within a housing condition (GI or IG) reached 1 g. Survival probability was significantly greater in mice in the IG housing condition compared to those in the GI housing condition (47% versus 19%, respectively). Additionally, the median survival time following the initiation of chemotherapy was greater for mice in the IG than for mice in the GI condition (24.5 days versus 15.0 days, respectively). These findings suggest that a psychosocial stressor, social housing condition, can significantly influence chemotherapeutic efficacy.

Arachidonic acid products-mediated contraction induced by bradykinin in relaxed mesenteric arterial rings from Holtzman rats

This study describes the contractile action of bradykinin on rat isolated mesenteric arterial rings and a possible mechanism responsible for this action. Bradykinin induced dose-dependent contraction of relaxed mesenteric arterial rings from Holtzman rats, but not from Wistar rats. A second bradykinin challenge in the same ring induced a very small effect or no effect at all. Destruction of the endothelium did not modify the response to bradykinin. des-Arg9-[Leu8]bradykinin failed to antagonize bradykinin's action. HOE 140 (D-Arg- [Hyp3, Thi5,D-Tic7,Oic8]bradykinin) reduced bradykinin-induced contractions. Indomethacin abolished the contractile response to bradykinin; prostaglandin F2 alpha induced a long-lasting contraction, dissimilar from that induced by bradykinin; L-655,240 (3-[1-(4-chlorobenzyl)-5-fluoro-3-methyl-indol-2-yl]-2,2-dimethyl propanoic acid), an antagonist of the thromboxane receptor, inhibited bradykinin-induced contractions. These results suggest that bradykinin-induced contraction in mesenteric arterial rings is indirect, through activation of bradykinin B2 receptors, resulting in liberation of prostanoids from outside the endothelium. Thromboxane A2 is probably an intermediate in this response but we cannot exclude the participation of other prostanoids.

Effect of surrogate fostering on splenic lymphocytes in fetal ethanol exposed rats

This study evaluated the effects of surrogate fostering as a procedure to control for postnatal effects of ethanol on the maternal female that may indirectly affect the offspring. Effects of fostering on the development of splenic lymphocytes, as well as possible differential effects of fostering on female and male offspring were examined. Litters from prenatal ethanol exposed (E), pair-fed (PF), and ad libitum-fed control (C) conditions were fostered at birth to surrogate untreated dams who had given birth within the same 12-hr period, or were reared by their biological mothers. At 15 and 60 days of age, offspring from each of the conditions were sacrificed and splenic leukocytes were enumerated and analyzed for expression of differentiation antigens, using flow cytometry. At 15 days of age, fostering reduced the percentages of CD45RA+ and CD5+ cells in E compared with PF and in PF compared with C offspring, and reduced the percentage of CD4+ cells in E compared with C offspring. Fostering also had differential effects on E and C offspring, resulting in reduced percentages of CD45RA+ and CD5+ cells in fostered E compared with nonfostered E offspring, but increased percentages of CD45RA+, CD5+, and CD8+ cells in fostered C compared with nonfostered C offspring. Fostering also down-regulated CD5 antigen expression in E compared with C offspring and up-regulated CD4 antigen expression in C offspring compared with their nonfostered counterparts. At 60 days of age, E females overall had higher percentages of CD45RA+ cells compared with C females and higher percentages of CD4+ cells compared with PF and C females. Nonfostered E females had higher percentages of CD5+ cells than nonfostered C females. In contrast, E males overall had greater percentages of CD4+ cells compared with PF and C males. Among males, the percentage of CD5+ cells was increased in nonfostered E compared with nonfostered C, whereas the percentages of CD45RA+ and CD5+ cells were decreased in fostered E males compared with nonfostered E. For both females and males in the nonfostered condition there were no effects of prenatal ethanol treatment on differentiation antigen expression. However, after fostering, E females had higher CD45RA and CD5 antigen expression compared with PF and C females, whereas E males had increased CD4 antigen expression and C males had decreased CD5 antigen expression compared with their nonfostered counterparts. These data demonstrate that fostering at birth has differential effects on splenic lymphocyte populations in E, PF, and C offspring. Moreover, the effect of fostering varies with age and has differential long-term effects on female and male offspring. Thus, rather than serving as a control for indirect maternal effects of ethanol on offspring, fostering appears to be a treatment in itself and may actually confound the effects of prenatal ethanol exposure by differentially affecting E, PF, and C females and males.

Retrograde percutaneous gastrostomy and gastrojejunostomy in 505 children: a 4 1/2-year experience

PURPOSE

To evaluate a technique of retrograde insertion of gastrostomy and gastrojejunostomy tubes with radiologic guidance in children.

MATERIALS AND METHODS

During a 4 1/2-year period, 511 patients underwent attempted insertion of gastrostomy or gastrojejunostomy tubes. Patients' ages ranged from premature to 18.6 years (mean age, 3.8 years), and weight range was 0.8-86.0 kg (mean weight, 12 kg). The charts of 453 patients were reviewed.

RESULTS

Placement was unsuccessful in six patients because of colonic interposition (n = 2), microgastria (n = 2), or hepatosplenomegaly (n = 2). Initial placement was a gastrostomy tube in 436 patients and a gastrojejunostomy tube in 69 patients. Sixty-eight gastrostomy tubes were converted to gastrojejunostomy tubes. Early complications (< 30 days) included skin infection (n = 11), stoma irritation (n = 20), and tube dislodgment (n = 6). Late complications included stoma irritation (n = 29), skin infection (n = 23), tube leakage (n = 14), and discomfort during feeding (n = 15). Two complications necessitated surgery: extragastric misplacement and small-bowel transgression. There were no tube-related deaths.

CONCLUSION

Percutaneous retrograde placement of gastrostomy or gastrojejunostomy tubes safely and effectively provides long-term nutrition for children. A team approach is essential to provide service to this cumulative population.

Electromyographical evidence for exercise-induced diaphragm fatigue in patients with chronic cervical cord injury or prior poliomyelitis infection

The purpose of this study was to determine, in exercising patients, how much diaphragm force increases before electromyographical evidence of diaphragm fatigue occurs. The study was performed in ten male patients with complete cervical cord injury (CCI) at the C5 to C8 levels, and five male patients with prior poliomyelitis infection (PPI) requiring chronic treatment with intermittent positive pressure ventilation (IPPV) at night. We studied the time course of the diaphragmatic tension-time index (TTdi), the centre frequency (CFdi) of the diaphragm electromyogram (EMGdi) power spectrum, and the ventilatory parameters, during steady-state submaximal arm/leg exercise. During exercise, early signs of diaphragm fatigue were present in seven out of 10 CCI patients and in four out of five PPI patients, as indicated by a reduction in CFdi. The increase in TTdi achieved before reductions in CFdi occurred was twofold in both the CCI and PPI patients. All patients except for the PPI patients, who demonstrated a reduction in CFdi, showed an increase in minute ventilation (VE), achieved by increasing both their tidal volume (Vt) and the breathing frequency (fb). The PPI patients demonstrating reductions in CFdi during exercise also increased their VE however, this was achieved by increasing fb while Vt remained constant. Following the reductions in CFdi, the CCI patients further increased their TTdi throughout the exercise test, while the PPI patients reduced their TTdi values.

IN CONCLUSION

(1) During exercise, electromyographical evidence for diaphragmatic fatigue frequently occurred in the CCI and PPI patients studied; (2) Compared to the eightfold increase in TTdi seen in healthy subjects before reductions in CFdi occur, the TTdi values increased only two-fold before electromyographical evidence of diaphragm fatigue was present in these patients; (3) There is a clear discrepancy between the CCI and PPI patients who demonstrate electromyographical evidence of diaphragm fatigue, in terms of their ventilatory and TTdi responses.

Effect of maternal ethanol consumption on maternal and fetal calcium metabolism

Alcohol consumption can have deleterious effects on both adult and developing bone. The mechanism(s) by which alcohol affects bone, however, is unknown. This study investigated the possibility that alcohol affects bone by alterations in calcium (Ca) metabolism. Female rats were fed lab chow ad libitum (C, Control) or a liquid diet with (E, Ethanol) or without (PF, Pair-Fed) ethanol. After 2 weeks on their respective diets, the rats were bred and the experimental diets continued throughout gestation. Blood (dams only) and tissue were collected on day 21 of gestation. The Ca content of maternal bone showed a trend toward a decrease in E and PF compared with C dams. Ionic Ca (iCa) levels were decreased in the blood of the E compared with PF and C dams. Serum parathyroid hormone levels were elevated in the E compared with C dams, consistent with the low iCa levels. Serum levels of 1,25(OH)2D, however, were elevated only in the PF dams. Mean fetal body weight and fetal skeletal ossification were reduced in the E compared with PF and C groups, but no group differences were found in fetal Ca content. These results indicate that maternal ethanol consumption compromised the ability of the dam to regulate her blood iCa levels, possibly partly due to a failure to increase 1,25(OH)2D levels. The delays in skeletal development observed in the ethanol exposed fetuses, however, do not appear to result from impaired placental Ca transfer.