Analysis of the complications of the piggy-back technique in 1,112 liver transplants

BACKGROUND

The "piggy-back" technique has gained acceptance in adult orthotopic liver transplantation during the last few years, especially in European countries. At the moment, however, there is controversy over advantages or specific complications (suprahepatic thrombosis or narrowing, etc.) related to this surgical technique. The aim of this study is to know of the immediate per-and postoperative morbidity and mortality rates in 1112 orthotopic liver transplantations performed with a vena cava preservation technique.

METHODS

All liver transplant units in Spain were sent a questionnaire on retrohepatic vena cava preservation during orthotopic liver transplantation. The number of orthotopic liver transplantations that had been performed in the seven centers that answered the questionnaire, because the beginning of the program, was 1674, with the vena cava preservation technique used in 1112.

RESULTS

Twenty-eight patients (2.5%) had intraoperative complications related to the vena cava preservation technique, which were treated during the operation. Eleven patients (1%) had early postoperative complications (first week), the most frequent (nine cases) being an acute Budd-Chiari syndrome in the first 48 hr. Three patients developed symptoms of massive ascites between 2 and 3 months (late postoperative complications), with patency of the retrohepatic cava verified by cavography. A hemodynamic study revealed a hyperpressure at the suprahepatic veins. This chronic Budd-Chiari syndrome was controlled in all patients with diuretics. Only six patients (0.5%) died as a result of complications related to the "piggy-back" technique. These complications were more frequent when venous reconstruction was done using two suprahepatic veins than when the three veins were used (P<0.001).

CONCLUSIONS

The vena cava preservation technique can be used routinely in orthotopic liver transplantation because it is safe and efficient and involves few surgical complications especially if for venous reconstruction we use the patch obtained by joining the three suprahepatic veins.

Characterisation of the lpdA gene from Neisseria meningitidis by polymerase chain reaction, restriction fragment length polymorphism and sequencing

P64k protein from Neisseria meningitidis is well recognised in sera from individuals convalescent from meningococcal disease or vaccinated with the Cuban antimeningococcal vaccine VA-MENGOC-BC. The presence of the protein in more than 80 meningococcal strains has also been verified. It is immunogenic in animal models and the antibodies elicited show bactericidal activity against meningococci. To further investigate at the molecular level whether lpdA, the gene coding for P64k protein, is conserved among different N. meningitidis strains, a total of 20 strains isolated from different geographic areas were differentiated on the basis of restriction fragment length polymorphism (RFLP) patterns after polymerase chain reaction (PCR) amplification of the lpdA gene and restriction endonuclease digestion with HpaII. Although a total of five different PCR-RFLP patterns were present, nucleotide sequence determination showed that identity levels were as high as 93-99% among the N. meningitidis strains analysed.

[Delayed diagnosis of Duchenne muscular dystrophy in Chile]

BACKGROUND

Duchenne muscular dystrophy is the most frequent neuromuscular disease in children.

AIM

To determine the causes of delayed diagnosis of the disease.

PATIENTS AND METHODS

The clinical records of 61 children diagnosed as Duchenne progressive muscular dystrophy were analyzed.

RESULTS

the first symptoms of the disease were noticed at a mean age of 1.5 years. Parents consulted at the mean age of 3 years, but the accurate diagnosis was made at a mean age of 5.7 years. In only 15% of children, the disease was diagnosed in the first four years of age. Less than 20% of children were referred for an adequate study and the rest were managed mainly as flat feet.

CONCLUSIONS

Duchenne dystrophy is the most common neuromuscular disorder in children, with an incidence of 1 in 3679 male newborns. The lack of recognition of non specific symptoms such as retardation in independent walking and frequent falls as forms of presentation, is probably the most important cause of diagnostic delay. Strong recommendation is made to measure creatinphosphokinase and to study every male child that is not walking independently by the age of 18 months.

Protection against Boophilus annulatus infestations in cattle vaccinated with the B. microplus Bm86-containing vaccine Gavac. off

Tick infestations by Boophilus spp. constitute a major problem for the cattle industry in tropical and subtropical areas of the world. The use of traditional control methods has been only partially successful and tick infestations remain a serious problem. Recently, the gut antigen Bm86 was isolated from B. microplus. Recombinant preparations of this antigen have been used in vaccines for the control of B. microplus infestations. However, in several regions of the world, B. microplus coexists with other Boophilus species, mainly B. annulatus and B. decoloratus. Therefore, there is a need for the simultaneous control of infestations by different Boophilus species. To test the capacity of the P. pastoris-derived Bm86 antigen preparation (Gavac, Heber Biotec S.A., Havana) to control B. annulatus infestations, controlled experiments were conducted in Mexico and Iran. Cattle were vaccinated with Gavac or not vaccinated and then artificially infested with B. annulatus larvae. The results showed for the first time a high protection efficacy (> 99.9%) of Gavac in the control of B. annulatus infestations. These results support the application of Bm86-containing vaccines for the control of Boophilus spp. infestations.

The development of monoclonal antibodies for the therapy of cancer

Monoclonal antibodies (Mabs) were first described by Köhler and Milstein in 1975. Not only did this discovery lead to a Nobel prize, but it created an enormous scientific field that has now become a multimillion dollar industry. Mabs made the transition from laboratory reagents to clinical diagnostics very quickly. However, their development as therapeutic agents was, as predicted, more costly and time-consuming. Indeed, clinicians and scientists were required to learn a new set of rules for using these large, immunogenic, targeted agents in humans. Nevertheless, in 1997 the first Mab was licensed in the U.S. and several others will soon follow. In this review, we discuss Mab-based strategies for the treatment of cancer. We compare native, fragmented, recombinant and chimeric antibodies, bispecific antibodies, immunoconjugates, and immunoliposomes. The rationale for their development, their advantages, their in vitro and in vivo performance, and their clinical usefulness are discussed.

Elimination of an HuIFN alpha 2b readthrough species, produced in Escherichia coli, by replacing its natural translational stop signal

When human interferon-alpha 2b (HuIFN alpha 2b) was expressed intracellularly in Escherichia coli as insoluble aggregates, a HuIFN alpha 2b molecular species of high molecular weight was detected, even after immunoaffinity chromatography and characterized by mass spectrometry and automatic sequencing. This HuIFN alpha 2b species was synthesized by an inefficient reading of the UGA natural stop codon, stopping the translation at another UGA in frame placed 10 codons downstream of the HuIFN alpha 2b stop signal. To avoid this translational readthrough process the UGA termination codon was replaced by UAA, which is frequently used in highly expressed E. coli genes. Simultaneously, almost all the HuIFN alpha 2b gene 3' noncoding region was removed. Analysis by SDS-PAGE and enzyme-linked immunosorbent assay revealed the elimination of the undesired HuIFN alpha 2b molecular species and an almost twofold increase in the expression level. These results indicate that both factors, the stop codon used and the length of the transcription unit should be taken into account when the expression in E. coli of heterologous proteins is desired.

Expression in Escherichia coli of the lpdA gene, protein sequence analysis and immunological characterization of the P64k protein from Neisseria meningitidis

By making use of recombinant DNA technology it is possible to characterize meningococcal outer membrane proteins (OMPs) capable of stimulating a host immune response. The lpdA gene, which codes for an OMP (P64k) from Neisseria meningitidis, was cloned in Escherichia coli. The recombinant protein was recognized by sera from patients convalescing from meningococcal disease. The monoclonal antibodies obtained against the recombinant protein recognized the natural protein on a Western blot, and monoclonal antibody 114 was assayed in ELISA with a panel of 85 N. meningitidis strains. The protein was recognized in 81 strains (95.3%); the strains that were not recognized were neither epidemic nor isolated from systemic disease. The complete amino acid sequence of P64k was obtained by automatic sequencing and MS.

Trypanosoma (Schizotrypanum) cruzi: histopathology in mice infected with strains isolated from Didelphis marsupialis from the valley of Caracas (Venezuela)

The histopathological alterations produced in NMRI strain mice by isolates of Trypanosoma cruzi from Didelphis marsupialis captured near human dwellings in the valley of Caracas, Venezuela are described. The donor opossums showed pseudocysts and amastigotes and trypomastigotes only in the heart muscle, and few areas of discrete inflammations and lysis of some muscle cells. Mice were parasitized in the heart, skeletal muscle, jejunum, colon, liver, lung, urinary bladder, penis, seminal vesicle, prostate, pancreas, and brain. All the isolates produced histiolymphocytic inflammation, severe in cardiac and skeletal muscle, and light in the smooth muscle of the intestine and urinary bladder; certain of the isolates produced destruction of muscle fibers. These findings, together with the morphology and behavior reported in previous papers, suggest that the isolates from this mammal reservoir and from the local vector (Panstrongylus geniculatus) belong to the same type. The possible venereal transmission through the parasitosis of the urogenital system is discussed. The necessity for characterization of strains of the parasite that have been isolated from areas of intense urbanization, where the ecological changes have reduced the number of host species, is emphasized; such studies may help to clarify the extreme heterogeneity of T. cruzi and the parasitoses it induces.

Two different 5' splice site mutations in the growth hormone gene causing autosomal dominant growth hormone deficiency

Four distinct types of isolated growth hormone deficiency (IGHD) have been described to date. Of these IGHD type II has been defined as having a dominant mode of inheritance. We performed a molecular genetic analysis of two patients clinically characterized as IGHD type II. One of the patients and her father shared a heterozygous G-A transition in the first 5' donor splice site of intron III. The second father and daughter studied also showed a heterozygous G-A transition in the fifth base from the 5' donor splice site in the same intron. Both mutations altered the correct splicing of the growth hormone pre-mRNA when the corresponding genes were expressed in COS-7 cells. We propose that both inherited mutations are responsible for IGHD type II in these patients.

Synanthropic rodent reservoirs of Trypanosoma (Schizotrypanum) cruzi in the valley of Caracas, Venezuela

Direct blood examination and xenodiagnosis of 47 synanthropic rodents (Rattus rattus, R. norvegicus, Mus musculus) captured in the valley of Caracas, Venezuela, revealed trypanosomal infections in 12 R. rattus, 10 with T. lewisi and 2 with T. cruzi. Of the latter the course of parasitemia, the pleomorphism of the bloodstream trypomastigotes, tissue in naturally and experimentally infected rats and mice, host mortality, morphology of fecal parasites in Rhodnius prolixus used for xenodiagnosis, and infectivity of the bug feces for NMRI mice, were all characteristic of Trypanosoma (Schizotrypanum) cruzi. One rat, with a patent parasitemia, had numerous nests of amastigotes in cardiac muscle and moderate parasitism of the smooth muscle of the duodenum and of skeletal muscle. Mice inoculated with fecal flagellates from the bugs had moderate tissue tropism in the same organs and also in the colon and pancreas. The possible role of R. rattus in the establishment of foci of Chagas' disease in Caracas is discussed.

Dual transduction signaling by a Xenopus muscarinic receptor: adenylyl cyclase inhibition and MAP kinase activation

Using transient transfection of COS-7 and human embryonic kidney 293 cells, we studied the functional properties of a previously cloned muscarinic Xenopus receptor [Herrera et al. (1994): FEBS Lett 352:175-179] and its coupling to adenylyl cyclase (AC) and mitogen-activated protein kinase (MAPK) pathways. Expression of the Xenopus muscarinic receptor results in the inhibition of AC activity and activation of the MAPK pathway through a mechanism that involves a Pertussis-toxin-sensitive G-protein and the G beta gamma subunits. The signal transduction properties of this receptor are similar to the mammalian m2 and m4 muscarinic receptors. These results strongly support the idea that inhibition of AC and MAPK activation, signaled out from the muscarinic oocyte receptor, are involved in the oocyte maturation process.

Molecular cloning and expression of an adenylyl cyclase from Xenopus laevis oocytes

We have cloned a cDNA that encodes a novel Xenopus laevis oocyte adenylyl cyclase (xlAC) using oligonucleotides against conserved mammalian adenylyl cyclase regions. The isolated cDNA is 4372 bp long with an open reading frame of 4065 nucleotides which encodes a protein of 1355 amino acids. Comparison of the deduced amino acid sequence with previously cloned mammalian adenylyl cyclases shows a low identity, 19.7% with type 2 rat adenylyl cyclase and 24.2% with type 4 rat adenylyl cyclase, indicating that this Xenopus isoform represents a new member of this protein family. Gene expression studies of the xlAC by reverse PCR showed that this gene is expressed in all oogenesis stages but not during early embryogenesis. Expression of the xlAC in COS-7 cells resulted in increased basal AC activity, that was stimulated by forskolin, Gpp(NH)p and aluminium fluoride, and was insensitive to calcium and calcium-calmodulin (Ca2(+)-CaM).

Patterns of recurrence following pelvic exenteration and external radiotherapy for locally advanced primary rectal adenocarcinoma

BACKGROUND

Local recurrence remains the main site of failure after pelvic exenteration for locally advanced primary rectal adenocarcinoma. This is a report on the patterns of recurrence in a group of such patients treated with pelvic exenteration and radiotherapy.

METHODS

Between 1980 and 1992, we treated 49 patients. Thirty-one received preoperative radiotherapy (pre-RT), 4,500 cGy. Six weeks later, we performed posterior pelvic exenteration (PPE) in 21 patients, and total pelvic exenteration (TPE) in 10. Nine patients received postoperative radiotherapy (post-RT), 5,000 cGy after a PPE. Nine patients had surgery only, PPE (n = 7) and TPE (n = 2).

RESULTS

Surgical mortality occurred in 16% of those patients who received pre-RT. The median follow-up was 52 months. Recurrences occurred in 23% of those patients who received pre-RT (local, one; local/distant, one; distant, four); in 88% of those patients treated with surgery only (local/distant, four; distant, four); and in 11% of those treated with post-RT (distant, one). The 5-year survival for patients who received radiotherapy was 66 versus 44% for those treated with surgery only.

CONCLUSION

Local control of locally advanced primary rectal adenocarcinoma requiring a pelvic exenteration is improved by the addition of radiotherapy. When recurrences do occur they are predominantly at extrapelvic sites.

Cloning and sequencing of a dextranase-encoding cDNA from Penicillium minioluteum

A cDNA from Penicillium minioluteum HI-4 encoding a dextranase (1,6-alpha-glucan hydrolase, EC 3.2.1.11) was isolated and characterized. cDNA clones corresponding to genes expressed in dextran-induced cultures were identified by differential hybridization. Southern hybridization and restriction mapping analysis of selected clones revealed four different groups of cDNAs. The dextranase cDNA was identified after expressing a cDNA fragment from each of the isolated groups of cDNA clones in the Escherichia coli T7 system. The expression of a 2 kb cDNA fragment in E. coli led to the production of a 67 kDa protein which was recognized by an anti-dextranase polyclonal antibody. The cDNA contains 2109 bp plus a poly(A) tail, coding for a protein of 608 amino acids, including 20 N-terminal amino acid residues which might correspond to a signal peptide. There was 29% sequence identity between the P. minioluteum dextranase and the dextranase from Arthrobacter sp. CB-8.

Small bowel tumors: an overview

Tumors of the small bowel, both benign and malignant, are relatively uncommon and often present a diagnostic challenge as their symptoms are often vague. This review article outlines the incidence, presentation, diagnosis, and management of small bowel tumors.

Nitric oxide production during the hyperacute vascular rejection

A complete understanding of the biological mechanisms that take part in the hyperacute vascular rejection is necessary to prevent its development. Nitric Oxide (NO) release by the graft could be one of those mechanisms as cytokine induction of NO synthase in reticuloendothelial cells produces NO with cytotoxic activity. We have performed 20 heterotopic pig-to-dog kidney xenotransplantations in order to determine if cytotoxic NO is released during the hyperacute rejection. Nitrites and cGMP levels were determined in plasma samples taken from the graft artery and vein until vessel thromboses. NO synthase activity was measured in pieces from renal artery and renal tissue. The results show that after discordant xenotransplantation, inducible NO synthase is activated in the transplanted organ, indicating that NO can mediate host tissue damage during the hyperacute rejection.

Mercury determination by CV-AAS in wastewater and sewage sludge from a stabilization pond system

The mercury concentrations in wastewater and sewage sludge of a stabilization pond system have been evaluated. The system is built by three parallel facultative ponds followed by two systems of three maturation ponds in series. The samples of wastewater and sludge were digested using nitric acid and placed into a Parr-type bomb for 4 h at 110 degrees C. Mercury was measured by Cold Vapour Atomic Absorption Spectrometry (CV-AAS) at 253.7 nm with sodium tetrahydroborate as reductant. The methodologies were checked with an USEPA quality control sample, a standard reference material from NIST and with another method of mineralization (cold mineralization) showing good results. Concentrations of mercury in wastewater between 1.47 +/- 0.75 microgl(-1) have been found at the entrance of the system and 0.74 +/- 0.0 microgl(-1) at the exit, while in sludge the results were between 0.29 +/- 0.12 microgkg(-1) in the facultative pond and 0.04 +/- 0.02 microgkg(-1) in the second maturation pond (exit).

Normative data stratified by age and education for the Neuropsychological Screening Battery for Hispanics (NeSBHIS): Initial report

Neuropsychological assessment of monolingual Spanish-speaking people in the United States is both a common practice and an ethical dilemma. Lack of appropriate tests, the absence of norms, use of interpreters, and the multiplicity of in-house translations of commonly used measures add to the problem of accurate assessment. This paper helps address the lack of appropriate measures for the neuropsychological assessment of Latinos in the United States by providing a standardization of the Neuropsychological Screening Battery for Hispanics (NeSBHIS). Normative data on a sample of 300 Hispanic subjects stratified by gender, age, and education are provided. Current results reveal that not one measure of cognitive functioning is free from education effects. Both nonverbal measures and psychomotor speed measures were highly related to education. Age effects were noted on measures of psychomotor speed, visuospatial reasoning, and visuoconstructive skills. Gender effects were found on measures of psychomotor speed and language, with males achieving higher scores than females. The limitations of the current findings are considered. Further research for the validation of the NeSBHIS with clinical populations, as well as further normative data collection at the national and international levels, is needed.

Expression and folding of an interleukin-2-proinsulin fusion protein and its conversion into insulin by a single step enzymatic removal of the C-peptide and the N-terminal fused sequence

We report the expression in E. coli of a proinsulin fusion protein carrying a modified interleukin-2 N-terminal peptide linked to the N-terminus of proinsulin by a lysine residue. The key aspects investigated were: (a) the expression of the fused IL2-PI gene, (b) the folding efficiency of the insulin precursor when still carrying the N-fused peptide and (c) the selectivity of the enzymatic cleavage reaction with trypsin in order to remove simultaneously the C-peptide and the N-terminal extension. It was found that this construction expresses the chimeric proinsulin at high level (20%) as inclusion bodies; the fused protein was refolded at 100-200 micrograms/ml to yield about 80% of correctly folded proinsulin and then it was converted into insulin by prolonged reaction (5 h) with trypsin and carboxypeptidase B at a low enzyme/substrate rate (1:600). This approach is based on a single enzymatic reaction for the removal of both the N-terminal fused peptide and the C-peptide and avoids the use of toxic cyanogen bromide.

Intraoperative small bowel enteroscopy in familial adenomatous and familial juvenile polyposis

BACKGROUND

In familial adenomatous polyposis and juvenile polyposis, polyps can occur throughout the gastrointestinal tract.

METHODS

We report seven patients with familial adenomatous polyposis and two patients with juvenile polyposis who underwent small bowel enteroscopy at the time of exploratory celiotomy either for colectomy or other pathology.

RESULTS

Polyps in the jejunum and/or ileum were noted in five of nine (56%) patients at enteroscopy. In three of nine (33%) patients these polys were adenomatous. Two of these patients had polyps in the jejunum and in the ileum, whereas one patient had jejunal adenomas alone. These polyps were from 3 mm to 30 mm in size. The remaining two patients with polyps had lymphoid hyperplasia in the ileum. All three patients who had adenomas at intraoperative small bowel enteroscopy had duodenal adenomas at esophagogastroduodenoscopy. At the age of 14 years, one patient had an intramucosal carcinoma in a small bowel juvenile polyp.

CONCLUSION

Baseline small bowel enteroscopy should be considered at the time of surgical exploration in patients with asymptomatic familial adenomatous polyposis and juvenile polyposis. In patients with duodenal polyps, enteroscopy should be performed at the time of surgery. Biopsy and/or excision of larger polyps should be performed because these polyps may harbor a carcinoma.