Impact of Pregnancy on the Function of Transplanted Kidneys

INTRODUCTION

This study reviewed the course of pregnancies in terms of impact on renal function and delivery-related data among women who received kidney transplants in our unit.

METHODS

We reviewed the medical records of women transplanted between 1982 and 2002 who became pregnant. We recorded the data of medical, obstetrical, and transplant-related complications, plasma creatinine levels, and blood pressures at baseline, delivery, and 12 months after delivery.

RESULTS

Thirty women had 37 pregnancies. Immunosuppressive protocols included cyclosporine, ketoconazole, azathioprine, and prednisone in 22 patients or azathioprine and prednisone in 15. Renal function decreased significantly: mean creatinine levels at baseline, delivery, and after 1 year were: 1.19 +/- 0.38 mg/dL; 1.44 +/- 0.70 mg/dL; and 1.38 +/- 0.53 mg/dL, respectively (P = .023 and P = .004 vs baseline respectively). Systolic and diastolic blood pressures at delivery were higher than at baseline (134 +/- 19 and 86 +/- 14 mm Hg vs 126 +/- 21 and 79 +/- 13 mm Hg (P = .029 and P = .053, respectively). These values normalized 1 year later (128 +/- 21 and 80 +/- 16). Decreased use of antihypertensive drugs were the cause of poor blood pressure control (1.8 +/- 1.3 vs 0.9 +/- 0.7, P < .01). Blood pressure control improved following delivery. The most frequent complications were preeclampsia (18.9%), intrahepatic cholestasis (13.5%), and urinary tract infections (13.5%). There were five rejection episodes. Seven miscarriages took place and one mole. Eleven pregnancies were uncomplicated.

CONCLUSION

Renal transplantation is the best treatment for fertile women with end-stage renal disease who want to become pregnant. However, pregnancy is risky for the mother, fetus, newborn, and allograft.

Two-particle model to study fluctuations of scattered radiation: multiple-scattering effects

The intensity fluctuations of light scattered from a simple particle aggregate system consisting of two dipole-like particles separated by a fixed distance and floating freely in space are calculated numerically and analyzed statistically. The behavior of two statistical parameters, the second-order factorial moment of the intensity fluctuations and the probability of obtaining zero cross-polarized intensity, are studied as a function of both the particle polarizability and the interparticle distance. Effects of multiple-scattering processes on these statistical parameters are accounted for in particular.

Factors affecting the transformation of a pyritic tailing: scaled-up column tests

Two different methods for predicting the quality of the water draining from a pyritic tailing are compared; for this, a static test (ABA test) and a kinetic test in large columns were chosen. The different results obtained in the two experimental set-ups show the necessity of being careful in selecting both the adequate predictive method and the conclusions and extrapolations derived from them. The tailing chosen for the weathering tests (previously tested in shake flasks and in small weathering columns) was a pyritic residue produced in a flotation plant of complex polymetallic sulphides (Huelva, Spain). The ABA test was a modification of the conventional ABA test reported in bibliography. The modification consisted in the soft conditions employed in the digestion phase. For column tests, two identical methacrylate columns (150 cm high and 15 cm diameter) were used to study the chemical and microbiological processes controlling the leaching of pyrite. The results obtained in the two tests were very different. The static test predicted a strong potential acidity for the tailing. On the contrary, pH value in the effluents draining from the columns reached values of only 5 units, being the concentration of metals (<600 mg/L) and sulphate ions (<17,000 mg/L) very small and far from the values of a typical acid mine drainage. In consequence, the static test may oversize the potential acidity of the tailing; whereas large columns may be saturated in water, displacing the oxygen and inhibiting the microbial activity necessary to catalyse mineral oxidation.

Tumour spectrum of non-polyposis colorectal cancer (Lynch syndrome) on the island of Tenerife and influence of insularity on the clinical manifestations

Colorectal cancer is a complex disease from a genetic point of view because both genetic and environmental factors interact in its development. Only familial adenomatous polyposis (FAP) follows mendelian genetics, in that mutations of the APC gene lead to development of the tumours. Lynch syndrome is the most frequent form of hereditary colorectal cancer and appears to be associated with other types of extracolonic cancers. The genetic basis has been established as a defect in DNA mismatch repair genes, and there is genetic heterogeneity due to the involvement of several genes in this system. Germinal mutations in these genes predispose to appearance of the syndrome. The aim of this study is to describe the tumoral spectrum of 10 families, comprising a total of 488 individuals, from the island of Tenerife (Canary Islands) and to assess whether the geographical isolation of this population has changed any features of the tumoral spectrum of the syndrome in comparison with studies that cover larger geographical areas with more genetic exchange. From our results we can conclude that the genetic drift and consanguinity in this population with a demographic history of isolation did not significantly alter the tumoral spectrum of the syndrome. Our data confirm that families affected by Lynch syndrome are a high-risk population and should be closely monitored, since their careful supervision has been shown to be useful in preventing cancer. We also emphasize the importance of developing a complete family history that permits these families to be identified together with a mutational screening of DNA mismatch repair genes (mainly MLH1 and MSH2 genes) with the aim of a possible identification of members of a family that should be carefully monitored (the carriers of germline mutations in these genes), whereas the remaining members, originally, are no more at risk than the general population.

Age-related changes in the pharmacokinetics of marbofloxacin after intravenous administration in goats

The pharmacokinetics of marbofloxacin was studied in adult goats and 1-, 3- and 6-weeks-old kids after single dose i.v. dose of 2 mg/kg body weight. Drug concentration in plasma was determined by high-performance liquid chromatography (HPLC) and the data collected were subjected to compartmental kinetic analysis. Volume of distribution was relatively high in adult goats (Vss = 1.31 L/kg), and increased with age (Vss = 0.92 L/kg, 0.95 L/kg and 1.00 L/kg, in 1-, 3- and 6-weeks-old kids respectively). Total body clearance (Cl) also increased with age from 0.080 L/kg.h (1-week-old) to 0.097 L/kg.h (3-weeks-old), 0.18 L/kg.h (6-weeks-old) and 0.23 L/kg.h (adult goats). As a consequence of increased body Cl, area under the plasma concentration vs. time curve decreased with age (AUC = 27.46 microg.h/mL, 22.61 microg.h/mL, 11.86 microg.h/mL and 8.44 microg.h/mL in 1-, 3-, 6-weeks-old kids and adults, respectively) and a longer elimination half-life was found during the first 3 weeks of age (t1/2beta = 9.66 h, 8.25 h, 6.44 h and 7.18 h, in 1-, 3-, 6-weeks-old kids and adults, respectively). Mean residence time decreased with age from 11.86 h in 1-week-old kids to 9.63 h (3 weeks), 5.76 h (6 weeks) and 5.06 h in adult goats.

[Incorporation of cortical intercalary bone allografts. Experimental study on rabbits]

An experimental study was carried out on 40 rabbits in order to evaluate the incorporation of large intercalary bone allografts and the influence of freezing on the bone graft. In 36 rabbits resection of 3 centimetres of diaphysis of the tibia was carried out and the defect was rebuilt with different types of bone graft: fresh autograft and frozen autograft, fresh allograft and frozen allograft; osteosynthesis was carried out with two intramedullary Kirschner needles. Monthly radiological studies were made until the sacrifice of the animals, at 2, 4 and 8 months. A densitometric, histological and diaphanisation study of the tibias was made with Spalteholz's technique. In 24 animals 25 mg/kg of oxytetracicline was administered 3 and 6 days before sacrifice, to study the velocity of bone apposition in the graft. We observed a good and excellent radiological consolidation in 80% of the grafts (99% in the autografts and 66% in the allografts). The bone density showed a fall until the 4th month due to bone reabsorption except in the group of fresh allografts. The revascularization of the allografts was slower and poorer than the autografts, but with the same vascular pattern. Bone incorporation and neoformation were greater in the autografts without significant differences with the frozen allografts. The speed of bone apposition did not change with the different types of bone graft used. Freezing facilitated and accelerated incorporation and the quantity of bone neoformation of the allografts.

Pharmacokinetics, toxicities, and efficacies of sodium stibogluconate formulations after intravenous administration in animals

The pharmacokinetics and toxicities of free sodium stibogluconate (SSG) and two vesicular formulations of this drug (a nonionic surfactant vesicular formulation of SSG [SSG-NIV] and SSG-NIV-dextran) were determined after treatment with a single intravenous dose in healthy dogs and were related to their antileishmanial efficacies in mice. Analysis of the curves of the concentrations in plasma after intravenous administration of SSG and SSG-NIV in dogs showed that both formulations produced similar antimony (Sb) pharmacokinetics. In contrast, treatment with SSG-NIV-dextran significantly modified the pharmacokinetics of the drug. The elimination half-life was four times longer (280 min) than that observed after administration of SSG (71 min) (P = 0.01), and the volume of distribution at steady state (V(SS)) was also increased (V(SS) for SSG, 0.21 liters/kg; V(SS) for SSG-NIV-dextran, 0.34 liters/kg [P = 0.02]), thus indicating that drug encapsulation favors the distribution of Sb into organs and increases its residence time in tissues. This would explain the superior antileishmanial efficacy of this formulation compared to those of the free drug in mice. No signs of toxicity were found in dogs after SSG and SSG-NIV administration. However, SSG-NIV-dextran treatment was associated with short-term toxicity, demonstrated by the development of chills and diarrhea, which cleared by 24 h postdosing, and hepatic dysfunction at 24 h postdosing (P < 0.05). The levels of all the biochemical parameters had returned to normal at 1 month postdosing. No signs of toxicity were observed in mice treated with all three formulations.

Description of a new auxiliary heterotopic partial liver transplantation technique with portal vein arteriolization of applicability in heterotopic liver xenotransplantation

OBJECTIVE

The aim of this study was to describe a new model of auxiliary heterotopic partial liver transplantation with portal vein arterialization.

MATERIALS AND METHODS

Three standard hepatectomies were performed in pigs. The left lateral lobe was surgically resected and portal vein arteriolization constructed by an end-to-side "Y" anastomoses between the distal to the celiac axis aorta and the portal vein.

RESULTS

The graft was placed in the left iliaca fossa using anastomoses of the donor infrahepatic inferior cava vein end-to-side to the host infrarenal inferior vein and the donor aortic stump with portal vein arteriolization end-to-side to the left iliac artery. After graft reperfusion, the 3 recipients showed intraoperative hypotension, which was treated with fluid administration and vasoactive drugs. At the end of the operation, the graft displayed normal arterial blood flow and good venous drainage. The donor liver graft appeared more red than the host liver, which was due to the increased arterial blood flow. One pig of 3 died at 24 hours after surgery, probably due to hypothermia. However, the other 2 pigs survived the procedure and remained stable. Echographic monitoring showed intrahepatic arterial expansion, which may be the result of high blood pressure due to the arteriolization procedure.

CONCLUSIONS

We have developed a novel and easy to perform technique that diminishes the number of anastomoses and does not involve vessels from other organs.

[Neurological explorations in Nuclear Medicine. A Spanish survey]

A representative Nuclear Medicine Service in Spain has two or three gammacameras. It performs neurologic studies one or two days at week wich account 2,1% of total workload. Brain Perfusion SPECT, specially in cognitive disorders, is the most frequent application. Neurooncology has a lower but established relevance. Neuroreceptors imaging are increasing in the last months. Emission tomography is obtained using a double-headed camera fitted with high-resolution parallel hole collimators and a half an hour total acquisition time. Datasets are reconstructed by filtered backprojection with Butterworth or Metz filtres. Images are visually interpreted with comparison to MRI and/or CT findings.

Influence of Escherichia coli endotoxin-induced fever on the pharmacokinetic behavior of marbofloxacin after intravenous administration in goats

The pharmacokinetic behavior of marbofloxacin was studied in seven healthy goats and in the same goats with induced fever after single-dose intravenous (i.v.) administration of 2 mg/kg b.w. Fever was induced by the administration of Escherichia coli endotoxin. Drug concentration in plasma was determined by high-performance liquid chromatography (HPLC). Drug distribution was somehow altered by fever as febrile goats showed a volume of distribution at steady-state (Vss = 0.72 +/- 0.15 L/kg) lower than normal goats (Vss = 1.19 +/- 0.33 L/kg). The elimination of the drug was also modified. Total plasma clearance (Cl) decreased from 0.24 +/- 0.12 L/kg/h in healthy animals to 0.13 +/- 0.05 L/kg/h in animals with endotoxin-induced fever, which is related to an increase in the area under the plasma concentration-time curve (AUC). Consequently, mean residence time (MRT) was also slightly increased in sick animals (MRT = 5.28 +/- 00.99 and 6.09 +/- 01.45 h, in healthy and febrile animals, respectively).

Development of interface in hydroxyapatite implanted in the middle ear of the rat: a light and scanning microscopy study

OBJECTIVE

The aim of this work is to study the chronology in the biological covering of the hydroxyapatite bioprostheses in the healthy middle ear of the rat.

STUDY DESIGN AND SETTING

Dense hydroxyapatite is implanted into the middle ear of 45 Long-Evans rats, between stapes and tympanic membrane. The sample was divided into 3 groups for morphologic, functional, and chemical studies at 15 days, 3 months, and 6 months after surgery, respectively.

RESULTS

The short-term studies reveal that the prostheses is surrounded by a fibrous epithelial tissue referred as the interface; it presents a marked inflammatory reaction that decreases gradually in the medium-term and long-term studies; in this way, we observe a progressive adhesion between implant and the contact tissues.

CONCLUSIONS AND SIGNIFICANCE

This model has enabled us to study the cell reaction produced by the contact of the prostheses with bone and soft tissue and their impact on the functional qualities of the prostheses.

Semen characteristics and plasma levels of testosterone after bilateral vasectomy in bucks

The effects of bilateral vasectomy on the seminal characteristics were assessed in six bucks of the Canarian breed. In addition, we tried to establish the effects of vasectomy on the plasmatic concentrations of testosterone and the libido of the bucks. Semen samples were collected once a week from 8 weeks before to 16 weeks after vasectomy; blood samples were collected prior to vasectomy, and then at once and 1 week after vasectomy and every 2 weeks from the week 4 to the end of the experiment. One week after the vasectomy, ejaculated spermatozoa were non-motile and the percentage of live spermatozoa was below 5% in all vasectomized males; in addition, the total number of cells/ejaculate was 3100 x 106 and 30 x 106 spermatozoa in the control and vasectomized males, respectively. Our results suggest that the vasectomized males may be used as oestrus detectors, without risks of accidental fecundating, only 1 week after vasectomy. Before vasectomy, no significant differences were observed in plasma levels of testosterone between the vasectomized and control males (5.4 +/- 1.2 and 3.9 +/- 1.4 ng/ml, respectively); from 4 to 12 weeks after vasectomy, a marked decrease in the testosterone concentration in all males (vasectomized and control bucks) was observed. From 12 weeks after vasectomy until the end of the experiment, four of the vasectomized males and the control males recovered their normal libido. The results suggest that vasectomy did not exert a remarkable effect on the steroidogenic functionality of the testicle.

[Ischemic cadiopathy in patients undergoing chronic hemodialysis]

We report a retrospective study of patients on chronic hemodialysis in whom a diagnosis of ischemic heart disease had been established. We compared the findings on coronary cineangiography and the treatment (medical only, surgical revascularisation [CABG] and percutaneous transluminal coronary angioplasty [PTCA]) with the early and late evolution. From a population of 2,287 patients on chronic hemodialysis treatment during the 5 year period 1994-1999, 83 patients who underwent coronary cineangiography after starting dialysis were selected. Their mean age was 63 +/- 9.4 (39-80) and the mean time on hemodialysis was 6 years (6 months-19 years).

RESULTS

65 patients (78%) had severe coronary lesions, 40% of whom had three vessel disease. 14 patients had medical treatment only (group 1), 23 had CABG (group 2) and 28 PTCA (group 3). Mortality within 30 days of intervention was 13% in group 2 and 21.4% in group 3. Global survival at two years was 82% in group 2 and 69% in group 3. Survival without angina at 6 and 24 months were 69% and 46% in group 2 and 55% and 22% in group 3 respectively. Survival without acute myocardial infarction at 6 and 24 months was 95% and 95% in group 2 and 89% and 64% in group 3. Data analysis using Cox proportional risk model showed that PTCA posed a higher risk of angina and death than CABG.

CONCLUSION

Surgery yielded better early and later results than angioplasty even in those patients with severe coronary artery disease.

[Multiple brown tumors in a female hemodialyzed patient with severe secondary hyperparathyroidism]

Skeletal brown tumours are relatively uncommon, and brown tumours that involve multiple bones are considered very rare. We describe a 29-year-old woman with chronic renal failure (CRF) who had undergone hemodialysis for 21 years and developed multiple brown tumours associated with severe secondary hyperparathyroidism. Computed tomography (CT) revealed multiple brown tumours involving scapula, ribs, spine and sacroiliac bone. Microscopic analysis of the brown tumour showed dense infiltration of the marrow space by reactive fibroblastic tissue with irregularly distributed multinucleated osteoclastic giants cells and marked increase in hematopoietic elements.

Pharmacokinetics of marbofloxacin in mature horses after single intravenous and intramuscular administration

The pharmacokinetic behaviour of marbofloxacin, a new fluoroquinolone antimicrobial agent developed exclusively for veterinary use, was studied in mature horses (n = 5) after single-dose i.v. and i.m. administrations of 2 mg/kg bwt. Drug concentrations in plasma were determined by high performance liquid chromatography (HPLC) and data obtained were subjected to compartmental and noncompartmental kinetic analysis. This compound presents a relatively high volume of distribution (V(SS) = 1.17 +/- 0.18 l/kg), which suggests good tissue penetration, and a total body clearance (Cl) of 0.19 +/- 0.042 l/kgh, which is related to a long elimination half-life (t(1/2beta) = 4.74 +/- 0.8 h and 5.47 +/- 1.33 h i.v. and i.m. respectively). Marbofloxacin was rapidly absorbed after i.m. administration (MAT = 33.8 +/- 14.2 min) and presented high bioavailability (F = 87.9 +/- 6.0%). Pharmacokinetic parameters are not significantly different between both routes of administration (P>0.05). After marbofloxacin i.m. administration, no adverse reactions at the site of injection were observed. Serum CK activity levels 12 h after administration increased over 8-fold (range 3-15) compared with pre-injection levels, but this activity decreased to 3-fold during the 24 h follow-up period. Based on the value of surrogate markers to predict clinical success, Cmax/MIC ratio or AUC/MIC ratio, single daily marbofloxacin dose of 2 mg/kg bwt may not be effective in treating infections in horses caused by pathogens with an MIC > or = 0.25 microg/ml. However, if we use a classical antimicrobial efficacy criteria, marbofloxacin can reach a high plasma peak concentration and maintain concentrations higher than MICs determined for marbofloxacin against most gram-negative veterinary pathogens throughout the administration period. Taking into account the fact that fluoroquinolones are considered to have a concentration-dependent effect and a long postantibiotic effect against gram-negative bacteria, a dose of 2 mg/kg bwt every 24 h could be adequate for marbofloxacin in horses.

[Effect of sildenafil citrate on the cortical visual responses]

OBJECTIVE

To study the possible effect of oral sildenafil citrate on the response of cortical visual cells to visual stimulation.

METHOD

Multiunit activity was recorded from cortical area V2 of one behaving monkey. Spatio-temporal receptive field maps were obtained by using a reverse cross correlation technique and white noise visual stimulation before and after oral administration of sildenafil citrate.

RESULTS

The receptive field maps showed a reduction in response latency after administration of sildenafil citrate.

CONCLUSIONS

Since sildenafil citrate is an inhibitor of retinal phosphodiesterase-6, an enhancement on light sensitivity in the photoreceptors is proposed as the cause of the observed reduction in response latency (Arch Soc Esp Oftalmol 2002; 77: 241-246).

Is sperm cryopreservation at -150 degree C a feasible alternative?

A series of experiments was carried out to validate a -150 degree C ultra-low temperature freezer for its possible use to properly freeze and store semen. In the first part, crude sample handling was simulated to see whether temperature of stored samples was maintained within a safe range; also, the freezing point and latent heat of fusion plateau of a semen extender were monitored. In the second part, buck semen was (i) frozen in liquid nitrogen and stored in the ultra-low freezer, (ii) frozen and stored in the ultra-low freezer, and (iii) frozen and stored in liquid nitrogen, to compare sperm cryosurvival between freezing methods. Both, frequent removal of samples and long opening of the freezer door did not negatively affect stored sample temperature; latent heat of fusion plateau was 5 minutes long. Semen stored either at -150 degree C or at -196 degree C cryosurvived similarly after 2 days and after 2 months of cryopreservation.

Dissociation of the associative and visceral sensory components of taste aversion learning by tetrodotoxin inactivation of the parabrachial nucleus in rats

The parabrachial nucleus (PBN) has been proposed as the associative site for conditioned taste aversion. Previous evidence has shown that functional blockade of the PBN by tetrodotoxin (TTX) produces retrograde disruption of lithium-induced taste aversions in rats. However, given the PBN role in processing visceral cues and the long duration of the lithium-induced aversive effects, an interpretation based on lithium chloride processing deficits can not be ruled out. The aim of the present study was to use the unconditioned stimulus (US) pre-exposure phenomenon to explore the effect of PBN inactivation by intracerebral TTX microinjections on visceral processing. Three intraperitoneal (i.p.) lithium chloride injections (0.15 M; 2% b.w.) applied before the conditioning session, but not isotonic saline i.p. injections, interfered with the acquisition of a learned aversion to a cider vinegar solution (3%) in cannulated control rats. Bilateral PBN inactivation by TTX (10 ng) applied immediately after each LiCl injections disrupted the US pre-exposure effect, thus confirming its sensory role. However, PBN inactivation 30 min after LiCl injections did not interfere with the US pre-exposure effect, in spite of the fact that an identically timed PBN blockade after the acquisition trial disrupted the acquisition of taste aversions. These results stand for the associative role of PBN in taste aversion learning induced by lithium chloride, independent of its sensory role. It is concluded that PBN activity is required after the conditioning trial for the taste-visceral association to take place.

Experimental measurement of the statistics of the scattered intensity from particles on surfaces

We analyze the statistics of the co-polarized and cross-polarized scattered intensity from a flat substrate contaminated with spherical particles including multiple scattering between them. Both Gaussian and non-Gaussian regimes are considered. In particular, we focus on both the cross-polarized component and the probability of detecting zeros in the cross-polarized intensity, P(Icross=0). As it is shown, the latter gives information about particle interaction and can be measured with higher accuracy than other statistical parameters. A theoretical model for P(Icross=0) is presented for spherical Rayleigh scatterers. An scattering experiment was carried out to verify this model.