Valutazione Dello Stato di Nutrizione di Pazienti Portatori di Carcinoma Dell'Esofago, Sottoposti a Nutrizione Parenterale Totale

Six patients with carcinoma of the esophagus (proximal and middle one-third) underwent intravenous artificial nutrition (TPN) both during preoperative radiation therapy and during the periods preceding radical surgery. From admission on, their conditions were evaluated and followed according to an established pattern of assessment of the nutritional state. Besides a certain improvement of the nutritional state at the level both of the muscular and adipose tissues, the results showed the reliability and the reproducibility of the serial anthropometric indexes adopted. With regard to the biochemical indexes most commonly utilized for evaluating the nutritional state, the results confirmed the doubts already casted about the reliability of a great part of these indexes when applied to this specific kind of patients.

The race for mainstream gastrointestinal endoscopy: frontrunners

In recent years, gastrointestinal endoscopy has evolved and branched out from a primary naked-eye diagnostic technique to a multitude of sophisticated investigative and therapeutic procedures. While many of the new endoscopic techniques are currently too complex or expensive to make it to mainstream clinical practice, others are already bringing major progress to the management of digestive diseases. In this review we will discuss a selected group of the emerging techniques and technologies used to increase the diagnostic yield in the colon and small intestine, including Third Eye® Retroscopes®, colon capsule endoscopy, spiral enteroscopy and confocal laser endomicroscopy. We will also discuss over-the-scope clip devices, a relatively simple and inexpensive tool potentially capable of noninvasive closing intestinal perforations and allowing the removal of infiltrating tumors.

Infliximab in Crohn's disease: a look at the (not so distant) future

Although infliximab has brought about a major advance in the treatment of Crohn's disease (CD), several questions remain unanswered. In particular, there is no consensus regarding the best timing to use it in the ideal therapeutic algorithm. Another controversial issue is whether this medication should be given or not for life once proven effective in the individual patient. Therapy with infliximab has also been associated to the development of intestinal strictures in CD: hence, some authors have discouraged its use in their presence. Finally, given its powerful antiinflammatory action, infliximab could in theory be effective in preventing postsurgical recurrence of CD, an as yet almost inescapable consequence of "curative" surgery. This review will focus on and discuss the relevant recent literature related to these issues with special regard to the efficacy and safety of infliximab in the presence of intestinal strictures and the potential role of this medication in preventing recurrence after surgery.

Role of biologics and other therapies in stricturing Crohn's disease: what have we learnt so far?

BACKGROUND

Therapy of strictures, one of the most common complications of Crohn's disease (CD), remains a challenging task in gastroenterology. While infliximab is widely recognized as being very effective in active CD, it has been reported to cause strictures in some patients. As a consequence, essentially by inference, many clinicians have chosen not to use it in the presence of strictures.

AIMS

To find evidence in the available data that infliximab does not cause strictures and that there is no rational basis to avoid its a priori use when a stricture is already present. In addition, to review what is currently known on the general management of strictures in CD.

METHODS

Discussion of the data that led to the hypothesis of a causal association between infliximab and strictures. Review of the mechanisms and the risk factors for stricture development in CD; of the different types of CD-related strictures; of the available means to distinguish them, and of the literature related to the efficacy and safety of infliximab as well as other biologics and other therapies in different stricturing scenarios.

RESULTS AND CONCLUSIONS

Although larger controlled studies are due in the near future, current evidence indicates that infliximab does not cause strictures in CD. The drug appears safe and effective in the presence of an inflammatory stenosis while being predictably ineffective, but not harmful, in the presence of fibrosis. Different stricturing scenarios in CD must be clearly distinguished for proper management of this complication.

"Cervia II Working Group Report 2006": guidelines on diagnosis and treatment of Helicobacter pylori infection in Italy

Proper management of Helicobacter pylori infection in clinical practice--when supported by evidence-based data--is expected to produce substantial cost-efficacy advantages. This consideration has prompted the Cervia Working Group to organise a meeting of experts to update the National Guidelines on the diagnosis and treatment of H. pylori infection in Italy. Recommendations in the new European Guidelines were considered in the National setting, here in the light of factors such as the incidence of gastric cancer and gastric lymphoma, the accessibility to different diagnostic tools, the prevalence of bacterial resistance against antibiotics, and the availability of different drugs. The main revisions in respect to the previous guidelines include H. pylori eradication in non-ulcer dyspepsia patients and in non-steroidal, anti-inflammatory drug users, as well as in patients with idiopathic thrombocytopenic purpura and iron deficiency anaemia. The stool antigen test is now accepted as a valid test for confirmation of H. pylori eradication following therapy. New therapeutic approaches have been recommended for both first- (sequential therapy) and second-line (levofloxacin-based) treatment in our country.

[The importance of the airborne microorganisms evaluation in the operating rooms: the biological risk for health care workers]

The operating room is a complex environment, traditionally considered at high infectious risk, for both the patients and the health care workers, they can contract diseases, because of the exposure for relatively long times to various dangerous chemical, physical and biological factors. The biological contamination in the operating rooms is mostly imputable to airborne and bloodborne microorganisms, whose primary source represent the staff: patients and operating team, while either secondary sources are the contaminate air introduced from the VCCC system and the use of the infect instruments. About 10% of the hospital infections are determined by airborne bacteria and a variable fraction of these, not only in immunocompromised patients but also in healthy people, may cause the respirators pathologies. The aim of this paper was to estimate the microbial contamination, in 20 hospitals located in three regions of the South Italy, for a total 81 operating rooms. The results show that 17 of the 20 operating units and 45 out of 81 operating rooms examined are contaminated. Periodic inspections should be carried out in order to control and lower the biological risk for both the patients and the health care workers.

Cavernous transformation of the portal vein associated to multiorgan developmental abnormalities

Initial diagnosis of cavernous transformation of the portal vein (portal cavernoma) is rarely made in adults. Its main clinical manifestation is upper gastrointestinal hemorrhage due to variceal bleeding. More rarely, diagnosis is made from obstructive jaundice. In children, this condition is frequently associated to prehepatic portal hypertension and congenital anomalies, the most frequent of which are atrial septal defects or malformations of the biliary tract or of the inferior vena cava. We describe here a case of a 23-year-old female presenting with massive hematemesis due to the presence of esophageal and small intestinal varices. She had a cavernous transformation of the portal vein with prehepatic portal hypertension associated with heretofore unreported malformations such as right pulmonary hypoplasia, cardiac dextroposition, and right renal ectopia. A unifying hypothesis (e.g. an intrauterine vascular insult) to explain the pathogenesis of these defects seems unlikely. Appropriate tests failed to identify specific functional abnormalities in these organs. Although she bled more than once, the combination of sclerotherapy and beta-blockers has been, thus far, able to control the major clinical consequences of this disease.

Scientific publications in gastroenterology and hepatology in Western Europe, USA and Japan in the years 1992-1996: a global survey

AIM

To evaluate number and quality of publications in gastroenterology, hepatology and digestive endoscopy from Western Europe (Belgium, Denmark, France, Germany, Great Britain, Italy, the Netherlands, Spain, Sweden, Switzerland), Japan and USA over a recent 5-year period.

METHODS

We screened by computer for full liver/gastrointestinal-related articles and reviews the top 40% of journals (according to the annual rating of the SCI Journal Citation Reports; Institute for Scientific Information database) in most clinical and basic science disciplines in the years 1992-1996. To be credited with an article, a given country had to be the site of the first institution where the work was conducted. Papers were rated according to the impact factor of the Institute for Scientific Information and to the ratio impact factor/mean European impact factor. Data were also normalized for nondefense research and development expenditure.

RESULTS AND CONCLUSIONS

As randomly tested, the computer search had an error of +/- 5-10%. In Europe, Great Britain achieved the highest total impact factor and the highest number of papers. Most of the British impact factor came from publications in British journals. The total USA impact factor exceeded that of Europe by 20%. The average impact factor for a single paper was highest for the USA and, in Europe, for Germany. The temporal trend of total impact factor showed Spain improving by 9% per year, with Germany and Italy also displaying a substantial growth. Expressed per funds allocated in nondefense research and development, Great Britain and the USA had the highest cumulative impact factor.

Gastric mucosa as an additional extrahepatic localization of hepatitis C virus: viral detection in gastric low-grade lymphoma associated with autoimmune disease and in chronic gastritis

The hepatitis C virus (HCV) has been linked to B-cell lymphoproliferation and autoimmunity, and has been localized in several tissues. The clinical observation of an HCV-infected patient with Sjögren's syndrome (SS) and Helicobacter pylori (HP) positive gastric low-grade B-cell non-Hodgkin's lymphoma (NHL), which did not regress after HP eradication, led us to investigate the possible localization of HVC in the gastric microenvironment. HCV genome and antigens were searched in gastric biopsy specimens from the previously mentioned case, as well as from 9 additional HCV-infected patients (8 with chronic gastritis and 1 with gastric low-grade B-cell NHL). HCV-specific polymerase chain reaction (PCR) and immunohistochemistry procedures were used. The gastric B-cell NHL from the patient with SS was characterized by molecular analyses of B-cell clonality. HCV RNA was detected in both the gastric low-grade B-cell NHL and in 3 out of 6 gastric samples from the remaining cases. HCV antigens were detected in the residual glandular cells within the gastric B-cell NHL lesions, in glandular cells from 2 of the 3 additional gastric lesions that were HCV positive by PCR, and in 1 additional chronic gastritis sample in which HCV-RNA studies could not be performed. By molecular analyses, of immunoglobulin genes, the B-cell NHL from the patient with SS was confirmed to be a primary gastric lymphoma, subjected to ongoing antigenic stimulation and showing a significant similarity with rheumatoid factor (RF) and anti-HCV- antibody sequences. Our results show that HCV can localize in the gastric mucosa.

Colorectal cancer screening in Italy: feasibility and cost-effectiveness in a model area

OBJECTIVE

To evaluate the feasibility and cost-effectiveness of screening programmes for colorectal cancer in Italy. DESIGN; We compared five types of programmes: annual faecal occult blood testing, sigmoidoscopy (every 5 years), faecal occult blood testing plus sigmoidoscopy (every 1 and 5 years), colonoscopy (every 10 years) (all in the age group 55-69 years, last examination at 70 years) and 'filter' colonoscopy. The latter had to be performed in persons at 50 years of age and repeated every 10 years until the age of 70. Costs for the tests and colon cancer care were paid by the Regional Health Office to the hospitals performing the procedures/treatments.

SETTING

Data were applied to a small model area in northern Italy (Gemona, 80,000 inhabitants) with well-known demographic (age distribution) and epidemiological (colon cancer incidence) features.

RESULTS

All-inclusive 10-year costs per screenee and per death prevented (in US dollars) were: 965 and 77,200 for faecal occult blood testing; 436 and 15,500 for sigmoidoscopy; 1521 and 35,000 for sigmoidoscopy plus faecal occult blood testing; 510 and 15,100 for colonoscopy; 510 and 14,000 for 'filter' colonoscopy. With 'filter' colonoscopy the programme required 870 colonoscopies per year, while with colonoscopy 13,700 colonoscopies were needed at time zero.

CONCLUSIONS

In Italy, screening programmes based on sigmoidoscopy/colonoscopy are more cost effective than those based on faecal occult blood testing. 'Filter' colonoscopy at age 50 appears superior to the other types of endoscopy-based screening programmes because it utilizes, at any point in time, a much smaller fraction of available resources.

Intestinal leiomyosarcoma and gastroparesis associated with von Recklinghausen's disease

The rare association between intestinal leiomyosarcoma, von Recklinghausen's disease (type-1 neurofibromatosis) and gastroparesis is described. A 20-year-old male, diagnosed 12 years earlier as having pelvic von Recklinghausen's disease, presented with nausea and vomiting. A gastric scintigraphy demonstrated an extremely slow gastric emptying time in the absence of obvious causes for gastroparesis. A small ileal leiomyosarcoma was later found and removed by surgery. The latter was followed by a marked improvement in the clinical condition of the patient.

Family burden and coping strategies in schizophrenia: are key relatives really different to other relatives?

Subjective and objective burden, psychiatric symptoms and coping strategies in a sample of 90 key relatives and other relatives of patients with schizophrenia, living in two European countries, were explored by means of well-validated questionnaires. The levels of burden on key relatives did not differ significantly from those on other relatives. Moreover, the risk of developing psychiatric symptoms was similar in the two subject groups at both centres. Significant correlations were found between key relatives and other relatives concerning the adoption of emotion-focused coping strategies. These data contrast with the current belief that family burden in schizophrenia is mainly a burden of key relatives, and they emphasize the need to provide supportive interventions for as many relatives as possible.

Helicobacter pylori infection and autoimmune processes: an emerging field of study

Evidence is accumulating that Helicobacter pylori infection may be closely associated with autoimmunity. However, whether autoimmunity plays a causal role in the pathogenesis of some of the diseases attributed to this bacterium or whether it is rather an epiphenomenon remains to be determined. In this brief review, a summary is made of current knowledge regarding the potential general mechanisms by which Helicobacter pylori causes mucosal damage. A review is then made of the evidence linking this bacterium to the production of different gastric autoantibodies. Finally, the reported association between Helicobacter pylori infection and some known autoimmune diseases is discussed. Although the data are still not sufficiently complete to draw definite conclusions, autoimmunity appears to be an important aspect of this infection and will certainly become a major field of study in the next few years.

Gastric B-cell clonal expansion and Helicobacter pylori infection in patients with autoimmune diseases and with dyspepsia. A follow-up study

BACKGROUND

It is not clear whether gastric B-cell clonal expansion, a possible precursor of mucosa-associated lymphatic tissue (MALT) lymphoma, is exclusively linked to Helicobacter pylori infection and virulence.

METHODS

In this study we followed up, for up to 33 months, 16 VDJ polymerase chain reaction-positive patients (4 with dyspepsia, 9 with Sjögren's syndrome, and 3 with other autoimmune diseases). Of these, 12 were H. pylori-positive. In addition, in H. pylori-positive patients we tested whether the serum anti-cag-A (a potential marker of virulence) was preferentially associated with B-cell clonality.

RESULTS

In all but one patient clonality appeared temporally unrelated to H. pylori infection. The prevalence of anti-cagA was not higher in H. pylori/VDJ-positive patients than in controls.

CONCLUSIONS

These data indicate that, in addition to H. pylori, gastric B-cell clonality may be sustained by other agents/mechanisms. Anti-cag-A does not appear to be involved in the pathogenesis of clonality.

[Ethical aspects of randomized clinical trials]

Randomized clinical trials represent the final, essential link between basic medical research and human health. However, their conduction presents very complex ethical problems, since the patient is the actual target of the experiment. Proper randomization, informed consent, and preliminary disclosure of results create deep ethical conflicts between the role of caretaker and that of impartial observer, both played by the same doctor. The dilemma reproduces the conflict between two different ethics. One is based on the inalienable individual rights stemming from the concept of man as an end in himself and not a means to an end. The other, derived from utilitarian philosophies, is based on the benefit for society as a whole. If we agree that randomized clinical trials represent the best method to test the validity of a new treatment, there is no easy solution. The dilemma could be solved by separating the role of the family doctor, committed to the best treatment possible for his patient, from the role of the scientist, committed to the progress of science and humanity. The former is involved in the treatment of individual patients, the latter in clinical and scientific experiments of a therapeutic nature. The patient may trade his rights to the best possible cure for the safety and the efficiency guaranteed by the scientific institution conducting the trial. Trials on relevant issues--expected to produce important results and impeccably designed scientifically--could be endowed with the ethics of science per se and this could be considered equivalent to the individual rights waived by the patient.

Characterization of prelymphomatous stages of B cell lymphoproliferation in Sjögren's syndrome

OBJECTIVE

To determine whether the prelymphomatous stages of B cell lymphoproliferation in Sjögren's syndrome (SS) may be better characterized by the integration of clinical, pathologic, and molecular data, the latter focusing on the expansion, persistence, and dissemination of clonal B cells in the course of the disease.

METHODS

Multiple tissue lesions (synchronous from different tissues and metachronous from the same tissue) were evaluated in biopsy specimens obtained from 6 consecutive patients with SS who had an associated lymphoproliferative disorder. Fully benign gastric lesions were evaluated in tissue from an additional 11 patients with SS who had no associated lymphoproliferative disorder. Multiple and complementary molecular analyses of B cell clonality were used: Southern blot, polymerase chain reaction, single-strand conformation polymorphism, DNA sequencing, and hybridization with clonospecific oligoprobes. All the patients were then strictly followed up for the appearance of lymphoma.

RESULTS

Different scenarios of SS-associated B cell lymphoproliferation were identified: 1) the ongoing expansion of the same dominant clone, localized or disseminated, in tissue from 2 patients, 1 of whom later developed an overt B cell lymphoma; 2) different dominant clones in different synchronous or metachronous tissues from the remaining 4 patients with an associated lymphoproliferative disorder; and 3) small oligoclonal expansions in 7 of the 11 benign gastric lymphoid infiltrates.

CONCLUSION

Prelymphomatous B cell lymphoproliferation in SS was better characterized following integration of the findings. The different types of B cell clonal expansion (oligoclonal or monoclonal, smaller or larger in size, fluctuating or established, localized or disseminated) may imply a different risk of lymphoma progression. An accurate clinical, histopathologic, and molecular characterization may therefore be crucial in future studies aimed at clarifying the pathobiology of SS-associated lymphoproliferation.

Hepatocellular sulfobromophthalein uptake at physiologic albumin concentrations: kinetic evidence for a high affinity/low capacity sinusoidal membrane system

BACKGROUND/AIMS

Controversy exists regarding the nature of the hepatocyte membrane transport system for sulfobromophthalein and other organic anions and its driving forces. Most studies have been performed in the absence of albumin, the plasma sulfobromophthalein binding protein, or using very low albumin concentrations. We have shown that in the latter case uptake kinetics reflect dissociation/diffusion events and not membrane transport. In contrast, without albumin very high sulfobromophthalein concentrations reach the cell surface and may overwhelm a high affinity/low capacity system operating in vivo. The aim of this study was to test the latter hypothesis.

METHODS

Sulfobromophthalein uptake was measured by rapid filtration in isolated hepatocytes without albumin (up to 13 microM sulfobromophthalein) and with 600 microM albumin (sulfobromophthalein:albumin from 0.03:1 to 1:1), a physiologic setting which greatly reduces the unbound BSP concentration. Unbound sulfobromophthalein concentration was estimated according to a three binding site model.

RESULTS

In the absence of albumin, kinetic parameters for sulfobromophthalein uptake were similar to those reported in the literature (K(m):7.1 +/- 1.2 microM; V(max): 452 +/- 37 pmol/min/5 x 10(4) cells). In the presence of albumin, sulfobromophthalein uptake displayed much greater affinity and much lower capacity (K(m): 80 +/- 11 nM; V(max): 60 +/- 9 pmol/min/5 x 10(4) cells).

CONCLUSIONS

These findings suggest that in the absence of albumin, resulting high sulfobromophthalein concentrations overload (and make undetectable) a high affinity/low capacity system operating at physiologic albumin concentrations (i.e. at low unbound sulfobromophthalein concentrations). Previously characterized transport systems may be operating only under defined conditions. These findings could explain the apparent controversy regarding the nature of the sulfobromophthalein transport system and its driving forces.

B-cell clonality and infection with Helicobacter pylori: implications for development of gastric lymphoma

BACKGROUND

Although Helicobacter pylori has been implicated in the pathogenesis of gastric mucosa associated lymphoid tissue (MALT) and MALT lymphoma, it is not known how it may trigger these lesions and whether there is an identifiable pre-neoplastic stage.

AIMS

To investigate the relation between MALT, H pylori infection, and B-cell clonality (a potential marker of pre-neoplastic lesions).

PATIENTS

141 subjects with simple dyspepsia.

METHODS

Gastric biopsy specimens from all patients were examined for MALT and H pylori. Of these, 25 consecutive MALT positive specimens were scored for features of MALT lymphoma and VDJ clonality studied by polymerase chain reaction.

RESULTS

Overall, prevalence was 62% for H pylori and 46% for MALT. VDJ clonality was frequent in the sub-group studied (nine of 25), mostly associated with lymphoid follicles (eight of nine or 89%), and with a high scoring for MALT lymphoma. VDJ clonality was equally frequent in patients with and without H pylori (seven of 20 and two of five or 35% and 40% respectively).

CONCLUSIONS

B-cell clonality is unexpectedly common in subjects with simple dyspepsia and MALT raising clinical management questions. These findings also suggest that the cascade MALT formation--B-cell clonality--MALT lymphoma may not be uniquely associated with H pylori infection.

Widespread clonal B-cell disorder in Sjögren's syndrome predisposing to Helicobacter pylori-related gastric lymphoma

Helicobacter pylori has been identified as a critical antigenic stimulus to the development of gastric lymphoma, but additional factors should be required for such evolution. This topic is now of major importance to clarify the pathobiology of gastric lymphomagenesis. Peculiar autoimmune diseases, such as Sjögren's syndrome, are well known to predispose to B-cell lymphomas. We report on a patient with Sjögren's syndrome and a widespread B-cell lymphoproliferative disorder. A pathological picture of low-grade lymphoma was observed in the stomach, concomitantly with H. pylori infection. However, the B-cell disorder was definitely nonmalignant in the other tissues involved, i.e., the parotid gland and lymph nodes, which are the characteristic targets of Sjögren's syndrome-associated lymphoproliferation. After H. pylori eradication, a dramatic regression of gastric lymphoma into chronic gastritis was observed, but no amelioration occurred in the parotid and nodal involvement. Multiple molecular analyses showed the expansion of the same B-cell clone in synchronous and metachronous lymph node, parotid, and gastric lesions before and after H. pylori eradication. Thus, H. pylori played a crucial role in the local boosting of B-cell lymphoproliferation, but the underlying B-cell disorder was that associated with the autoimmune disease and was nonmalignant. The comprehensive clinical, pathological, and molecular approach allowed us to then distinguish the role of peculiar individual predisposing factors and of local infection in the pathobiology of mucosa-associated lymphoid tissue-associated lymphoproliferation.

B cell clonality in gastric lymphoid tissues of patients with Sjögren's syndrome

OBJECTIVE

To determine the prevalence of mucosa associated lymphoid tissue (MALT) in the stomach and of a possible antigen driven proliferation, in patients with Sjögren's syndrome (SS).

METHODS

Twenty one patients with primary SS and 80 dyspeptic controls underwent upper endoscopy. Lymphoid tissue and Helicobacter pylori were assessed by histopathological analysis. Epstein-Barr virus (EBV) or human herpes virus-6 (HHV-6) genome were studied by polymerase chain reaction (PCR) DNA amplification. Two PCR VDJ procedures were used to detect immunoglobulin heavy chain (IgH) gene rearrangement.

RESULTS

Organised MALT was found in 33.3% of the patients, compared with 21.5% of the controls (NS). H pylori infection was seen in 71% of patients and 63% of controls. Genomic EBV or HHV-6 was found in a minor portion of SS gastric tissues. B cell expansion was detected in nine of the 21 patients. Infectious agents in the stomach might have contributed to B cell clonality only in 55.5% of the cases. No strict relationship was found between lymphoid follicles and clonality.

CONCLUSION

Lymphoid accumulation in the gastric mucosa is common in Sjögren's syndrome, but full evidence for an antigen driven B cell expansion could not be demonstrated. Only a portion of those with clonal B cell expansion had evidence of an infectious agent. Other unknown infectious agents or factors related to the underlying disease (autoantigen) and its tissue environment may have a further role as possible causes of B clonal expansion in the gastric mucosa.

Oleate uptake by isolated hepatocytes and the perfused rat liver is competitively inhibited by palmitate

Competition for uptake between long-chain free fatty acids has been difficult to document, because there has been no algorithm for computing unbound concentrations of two fatty acids simultaneously in solution with albumin. We modified an iterative procedure to permit this computation and studied initial [3H]oleate uptake by isolated hepatocytes and steady-state uptake by the single-pass perfused rat liver from 600 microM bovine serum albumin solutions containing various concentrations of oleate in the presence and absence of palmitate. In both systems, the Michaelis-Menten constant was significantly higher in the presence of palmitate than in its absence, whereas the maximal reaction velocity was unaltered, indicating competitive inhibition. In additional experiments employing the multiple transhepatic indicator-dilution technique, the influx rate constant and permeability-surface area product for oleate influx were significantly reduced by palmitate, confirming that the competition observed in the conventional perfused liver studies was at the influx step. Long-chain fatty acid uptake has now been shown to exhibit all the kinetic properties of facilitated transport and cannot be attributed solely to passive diffusion.

Helicobacter pylori, gastric MALT and B-cell clonality

MALT, or mucosa associated lymphoid tissue, is normally not present in gastric tissue. Its presence is often associated with persistent antigenic stimulation. MALT is a precursor of gastric MALT lymphoma, a low-grade lymphoma whose incidence recently appears to have increased. Although much epidemiologic and clinical evidence has linked both MALT and MALT lymphoma to Helicobacter pylori infection, it is not known whether other agents and or mechanisms may also play a role and whether there is a clearly defined pre-neoplastic lesion. In particular, the clinical significance of B-cell clonality remains unknown. In a recent study we attempted to define the role of H. pylori and MALT in the genesis of B-cell clonality in a northern Italian patient population referred to us for simple dyspepsia. The results show that B-cell clonality is unexpectedly frequent in these patients regardless of the presence of H. pylori infection. These observations raise the possibility that agents and mechanisms other than H. pylori may be involved in the genesis of MALT lymphoma. Indeed, other studies conducted by our group in patients with Sjögren's syndrome indicate that genetic/immunologic factors and possibly viruses may play a role. The high prevalence of B-cell clonality in an otherwise healthy population suggests either that most of these patients are at risk of developing MALT lymphoma (in which case this condition at the moment may be greatly underdiagnosed) or that B-cell clonality is a very early step in the development of neoplasia, which requires several other factors and which will occur only in a restricted fraction of these patients. Careful follow-up studies will provide an answer to this question.

The hepatocellular uptake of free fatty acids is selectively preserved during starvation

BACKGROUND/AIMS

The liver loses protein during fasting. This study sought to determine if hepatic protein loss during fasting selectively preserves functions important to survival such as uptake of fatty acids, which are major energy substrates in that condition.

METHODS

Initial [3H]oleate uptake and efflux rates in hepatocytes from starved (for 48 hours) and fed male rats were measured in media containing 250 mumol/L albumin at oleate/albumin ratios of 0.2:1-2:1. Uptake rates of sulfobromophthalein, taurocholate, and glucose were also determined.

RESULTS

Initial oleate uptake rate was saturable with respect to unbound oleate concentration. Maximum initial velocity expressed per cell number did not differ between fasted and fed animals, but measured cell volume and estimated surface area were decreased in starved vs. fed hepatocytes (921 +/- 21 vs. 1623 +/- 58 microns2, respectively; P < 0.001). Consequently, when expressed per surface area, maximum initial velocity was greater in starved cells (17 +/- 3 vs. 10 +/- 2 [pmol.min-1.micron2] x 10(-7); P < 0.02). Expressed similarly, oleate efflux was also greater from starved hepatocytes and was inhibited by an antibody to plasma membrane fatty acid binding protein (FABPpm). FABPpm concentration per unit area of plasma membrane also increased in starved hepatocytes (P < 0.05). By contrast, uptake rates of sulfobromophthalein, taurocholate, and glucose by starved hepatocytes were decreased when expressed per cell number and unchanged per unit area.

CONCLUSIONS

During fasting, the hepatocellular uptake mechanism for oleate is selectively preserved compared with those for sulfobromophthalein, taurocholate, or glucose.

Oleate uptake kinetics in the perfused rat liver are consistent with pseudofacilitation by albumin

We measured uptake of a representative free fatty acid, oleate, by the single-pass perfused rat liver at oleate:albumin molar ratios of 0.01 to 2:1. For each ratio, uptake was studied at albumin concentrations from 50 to 600 microM. When uptake velocity was plotted as a function of the albumin concentration, the data at each ratio exhibited a pseudosaturation pattern as previously observed in isolated cells (J Clin Invest 84: 1325). At a physiologic albumin concentration of 600 microM, a plot of uptake vs. unbound oleate concentrations was best fitted by the Michaelis-Menten equation (Vmax = 235 +/- 8.8 nmol.min-1.g.liver-1; Km = 130 +/- 12 nM). As the albumin concentration was increased from 50 to 250 microM, the unbound oleate clearance, calculated by either the undistributed sinusoidal or venous equilibrium models, increased progressively, in violation of conventional pharmacokinetic theory, indicating an enhancing effect of albumin on ligand uptake at low albumin concentrations. In contrast, there was no significant difference between measures of unbound clearance at albumin concentrations of 350 and 600 microM. To explain this phenomenon, the clearance data were examined for evidence of facilitation (accelerated dissociation of ligand:albumin complexes) by the clearance ratio test ("square root rule"). All deviations from the predictions of conventional theory were entirely attributable to pseudofacilitation. No data required explanation by a true facilitation model.

Unbound ligand drives hepatocyte taurocholate and BSP uptake at physiological albumin concentration

We have recently shown (D. Sorrentino, R.B. Robinson, C.-L. Kiang, and P.D. Berk. J. Clin. Invest. 84: 1325-1333, 1989) that, in a variety of isolated cell types, the uptake of oleate at physiological albumin concentrations is consistent with traditional pharmacokinetic theory (i.e., driven by unbound ligand). Lower albumin concentrations were associated with a deviant uptake pattern for which alternative theories have been proposed. Whether other classes of organic anions exhibit similar behavior is unknown. Therefore, we examined the effect of albumin on uptake of two widely studied organic anions, sulfobromophthalein (BSP) and taurocholate. Initial uptake velocity of [35S]BSP and [3H]taurocholate by isolated hepatocytes was studied employing a fixed albumin concentration and ligand-to-albumin molar ratios from 0.01:1 to 2:1 for taurocholate and 0.031:1 to 0.75:1 for BSP. In other experiments, albumin and ligand were altered in parallel, keeping their molar ratio constant. Unbound taurocholate concentrations were measured directly by equilibrium dialysis; unbound BSP concentrations were calculated from published data (K.J. Baker and S.E. Bradley. J. Clin. Invest. 45: 281-287, 1966). At 600 microM albumin, uptake of both ligands was a function of the unbound ligand concentration. At low ligand-to-albumin molar ratios and consequent unbound ligand concentrations this relationship was linear; over the entire range of unbound ligand concentrations studied, both ligands exhibited Michaelis-Menten kinetics, with definable maximal velocity and Michaelis constant values. At low albumin concentrations, the relationships between uptake and unbound ligand were unchanged for taurocholate; however, BSP exhibited altered kinetics similar to those observed with oleate. Nontraditional uptake kinetics at low albumin concentrations appear to correlate with very high affinity for albumin.

Characteristics of oleate binding to liver plasma membranes and its uptake by isolated hepatocytes

To clarify mechanisms of hepatic free fatty acid uptake, [3H]oleate uptake by isolated rat hepatocytes was studied, using solutions of 150 microM bovine serum albumin at oleate:albumin molar ratios of 0.033-6.7:1. Oleate partitioning between liver plasma membranes and albumin was also studied, and used to ascertain the membrane binding function for oleate. The experimental uptake curve was complex, but could be resolved by computer fitting into a sum of two components, one a saturable and the second a linear function of the unbound oleate concentration. The saturable component comprises > 90% of total oleate uptake when the oleate:albumin molar ratio is < 2.5, but < 50% when this ratio is > 5. Membrane binding also consisted of a sum of a saturable and a linear component. By comparison of the computer-fitted uptake and binding functions, separate rate constants for the transfer into the cell of the saturably and non-saturably bound oleate were estimated to be 0.7 s-1 and 0.05 s-1, respectively. The former is compatible with a specific, protein-mediated process. It is 15-times greater than the corresponding rate constant for transfer of non-saturably bound oleate into the cell, which in turn is similar to reported rates of non-specific 'flip-flop' of fatty acids across lipid bilayers. The observed kinetics are not consistent with models in which uptake occurs principally from the albumin-bound pool of oleate, or solely from the oleate which has partitioned passively into the lipid bilayer of the plasma membrane.

Sex differences in hepatic fatty acid uptake reflect a greater affinity of the transport system in females

In this study, we examined the hypothesis that the reported sex difference in hepatic free fatty acid (FFA) uptake involves the putative FFA transport system, the plasma membrane fatty acid binding protein (FABPpm). In hepatocytes isolated from both male and female rats, initial [3H]oleate uptake velocity reflected transmembrane influx and not subsequent metabolism and was a saturable function of the unbound oleate concentration. Although Vmax values were similar (61 +/- 2 vs. 65 +/- 5 pmol.min-1.5 x 10(4) cells-1 for females and males, respectively), the apparent Km was significantly smaller in females (40 +/- 4 vs. 90 +/- 11 nM; P less than 0.05), reflecting faster influx velocities in female cells over a range of unbound oleate concentrations. The oleate efflux rate constant was also greater in females (0.280 +/- 0.014 vs. 0.198 +/- 0.020 min-1; P less than 0.05) despite their greater hepatic content of cytosolic FABP. Finally, despite the greater rates of transmembrane FFA flux in female hepatocytes, the surface expression of FABPpm was virtually identical in the two sexes (2.5 +/- 0.5 vs. 2.4 +/- 0.4 microgram/10(6) cells). Collectively, these data indicate that at FFA-to-albumin ratios occurring in vivo the plasma membrane of female hepatocytes transports oleate bidirectionally at a greater rate than that of male hepatocytes. A sex-related difference in the functional affinity of FABPpm for FFA appears the most likely explanation for the greater oleate uptake in females.

Adipocyte differentiation of 3T3-L1 cells involves augmented expression of a 43-kDa plasma membrane fatty acid-binding protein

A previously described 43-kDa plasma membrane fatty acid-binding protein (FABPPM) was not observed by immunohistochemical methods in proliferating 3T3-L1 fibroblasts. However, it was detectable in plasma membranes by the second day of confluent growth, prior to accumulation of visible lipid droplets, and was strongly expressed in 8-day differentiated adipocytes. These observations were confirmed by extraction of plasma membrane proteins and subsequent immunoblotting. Kinetics of initial [3H]oleate uptake by both fibroblasts and adipocytes consisted of the sum of a saturable and a non-saturable component. During differentiation the saturable component increased progressively. Vmax increased from 3 to 25 to 110 pmol.s-1.mg cell protein-1 between the fibroblast, the 4-day, and 8 day adipocyte stages; Km was 24 nM in fibroblasts and approximately 55 nM in both 4- and 8-day differentiated adipocytes. By contrast, the rate constant for nonsaturable oleate influx decreased progressively from 0.026 to 0.010 ml.s-1.mg protein-1 between the fibroblast and 8 day adipocyte stages. In 8-day adipocytes saturable oleate uptake was inhibited by up to 55% by antibodies against rat liver FABPPM; these antibodies had no effect on uptake of 2-deoxyglucose or the medium chain fatty acid octanoate. They also had no effect on oleate uptake by fibroblasts. These studies support the hypothesis that FABPPM is a component of a saturable transport mechanism for long chain fatty acids.

Hepatocellular 22Na+ uptake: effect of oleate

Whether cellular oleate uptake is Na+ coupled remains controversial. Our present studies document that hepatocellular [3H]oleate uptake is unaltered by isomotic substitution of Na+ with K+, Li+, or sucrose in Hanks' HEPES buffer. In parallel studies 22Na+ uptake was significantly (P less than 0.02) increased by concentrations of alanine that yielded [3H]-alanine uptakes greater than 24% of basal 22Na+ uptake when both were expressed as nanomoles per minute per 10(6) hepatocytes. Although [3H]glutamine uptake exceeded this threshold, maximal specific [3H]taurocholate uptake did not. Consistent with the observations with alanine, addition of glutamine, but not taurocholate, to the incubations resulted in a significant increase in 22Na+ uptake. The ionophore monensin increased uptake of 22Na+ under all conditions. Both in the absence and in the presence of HCO3- (4 and 25 mM), specific [3H]oleate uptake was sufficient to elicit a readily detectable effect on 22Na+ uptake, if Na+ and oleate were cotransported. However, addition of 1 mM oleate did not affect 22Na+ uptake in the absence of HCO3- (5.4 +/- 0.6 vs. control 5.4 +/- 0.4 nmol.min-1.10(6) cells-1) as well as in the presence of 4mM HCO3- (10.4 +/- 1.8 vs. control 9.9 +/- 1.1) and 25 mM HCO3- (10 +/- 1.3 vs. control 10.8 +/- 0.5). These data indicate that the predominant component of hepatocellular oleate uptake is not directly associated with Na+ influx. They do not exclude, however, a more complex or indirect link.

Functional and morphological features of isolated hepatocytes preserved in University of Wisconsin solution

Although several studies suggest that hepatic graft failure after cold ischemia results from nonparenchymal cell damage, other data indicate that hepatocellular ATP content is significantly correlated with the transplantation success rate. In this study, we have conducted a systematic investigation of various aspects of cell viability and function of isolated hepatocytes stored at 4 degrees C for 24 and 48 hr in either University of Wisconsin solution or Hanks' HEPES buffer, a control solution clinically unsuitable for organ preservation. After 24 hr, hepatocytes stored in Hanks' HEPES buffer had viability (measured by trypan blue exclusion and ALT and lactic dehydrogenase leakage), transport function (measured by 22Na+ and [3H]taurocholate uptake) and cell size similar or only slightly altered when compared with freshly isolated and University of Wisconsin solution-stored hepatocytes. ATP content was decreased in both groups; however, the reduction was much greater in Hanks' HEPES buffer-stored cells. Furthermore, ATP regenerating capacity was greatly reduced in Hanks' HEPES buffer- stored but not in University of Wisconsin solution-stored hepatocytes. By 48 hr viability and function of Hanks' HEPES buffer-stored hepatocytes were decreased; University of Wisconsin solution afforded partial protection. When examined by light and electron microscopy, cells stored in both University of Wisconsin solution and Hanks' HEPES buffer for 24 hr appeared essentially normal except for the presence of numerous membrane blebs in the Hanks' HEPES buffer group. Tissue sections of livers preserved in Hanks' HEPES buffer but not in University of Wisconsin solution revealed the presence of extensive amounts of blebs in the sinusoidal lumen and loss of endothelial elements.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitation of plasma membrane fatty acid-binding protein by enzyme dilution and monoclonal antibody based immunoassay

A plasma membrane fatty acid-binding protein (h-FABPpm) has been isolated from rat hepatocytes. Analogous proteins have also been identified in adipocytes, jejunal enterocytes and cardiac myocytes, all cells with high transmembrane fluxes of fatty acids. These 43 kDa, highly basic (pI = 9.1) FABPpm's appear unrelated to the smaller, cytosolic FABP's (designated FABP's) identified previously in the same tissues. h-FABPpm appears closely related to the mitochondrial isoform of glutamic-oxaloacetic transaminase (mGOT), and both the purified protein and liver cell plasma membranes (LPM) possess GOT enzymatic activity. From their relative GOT specific activities it is estimated that h-FABPpm constitutes approximately 2% of LPM protein, or about 0.7 x 10(7) sites per cell. A monoclonal antibody-based competitive inhibition enzyme immunoassay (CIEIA) for h-FABPpm is described; it yields an estimate of 3.4 x 10(7) h-FABPpm sites per hepatocyte. Quantitated by either method, h-FABPpm appears to be a highly abundant protein constituent of LPM.

Plasma membrane fatty acid-binding protein and mitochondrial glutamic-oxaloacetic transaminase of rat liver are related

The hepatic plasma membrane fatty acid-binding protein (h-FABPPM) and the mitochondrial isoenzyme of glutamic-oxaloacetic transaminase (mGOT) of rat liver have similar amino acid compositions and identical amino acid sequences for residues 3-24. Both proteins migrate with an apparent molecular mass of 43 kDa on SDS/polyacrylamide gel electrophoresis, have a similar pattern of basic charge isomers on isoelectric focusing, are eluted similarly from four different high-performance liquid chromatographic columns, have absorption maxima at 435 nm under acid conditions and 354 nm at pH 8.3, and bind oleate with a Ka approximately 1.2-1.4 x 10(7) M-1. Sinusoidally enriched liver plasma membranes and purified h-FABPPM have GOT enzymatic activity; the relative specific activities (units/mg) of the membranes and purified protein suggest that h-FABPPM constitutes 1-2% of plasma membrane protein in the rat hepatocyte. Monospecific rabbit antiserum against h-FABPPM reacts on Western blotting with mGOT, and vice versa. Antisera against both proteins produce plasma membrane immunofluorescence in rat hepatocytes and selectively inhibit the hepatocellular uptake of [3H]oleate but not that of [35S]sulfobromophthalein or [14C]taurocholate. The inhibition of oleate uptake produced by anti-h-FABPPM can be eliminated by preincubation of the antiserum with mGOT; similarly, the plasma membrane immunofluorescence produced by either antiserum can be eliminated by preincubation with the other antigen. These data suggest that h-FABPPM and mGOT are closely related.

At physiologic albumin/oleate concentrations oleate uptake by isolated hepatocytes, cardiac myocytes, and adipocytes is a saturable function of the unbound oleate concentration. Uptake kinetics are consistent with the conventional theory

To reexamine the role of albumin in cellular uptake of long chain fatty acids, we measured [3H]oleate uptake by isolated hepatocytes, adipocytes, and cardiac myocytes from incubations containing oleate/albumin complexes at molar ratios from 0.01:1 to 2:1. For each ratio the uptake was studied over a wide range of albumin concentrations. In all three cell types and at any given oleate/albumin ratio, the uptake appeared saturable with increasing concentrations of oleate:albumin complexes despite the fact that the unbound oleate concentration for each molar ratio is essentially constant. However, the "Km" but not the "Vmax" of these pseudosaturation curves was influenced by substrate availability. At low albumin concentrations, uptake velocities did not correlate with unbound oleate concentrations. However, observed and expected uptake velocities coincided at albumin concentrations approaching physiologic levels and were a saturable function of the oleate/albumin ratios and the consequent unbound oleate concentrations employed. Hence, under the experimental conditions employed in this study using a variety of suspended cell types, oleate uptake kinetics were consistent with the conventional theory at physiologic concentrations of albumin.

The hepatocellular transport of sulfobromophthalein-glutathione by clofibrate treated, perfused rat liver

The hypolipidemic drug clofibrate is known to affect the hepatic transport of various organic anions including bilirubin, fatty acids and sulfobromophthalein. Changes in the rate of metabolism and/or intracellular transport have been claimed responsible for the effect. To evaluate these possibilities, the transport of sulfobromophthalein-glutathione, a model compound that does not require metabolism for biliary excretion, was studied in perfused livers isolated from clofibrate-treated and control rats. Cytosolic fatty acid binding protein and glutathione S-transferase activity were also measured. Clofibrate treatment significantly increased liver weight; as a result glutathione S-transferase activity (toward 1-chloro-2,4-dinitrobenzene) fell if expressed per gram of liver (4560 +/- 420 (SE) vs 7010 +/- 260 nmoles/min for clofibrate treated and controls respectively, p less than 0.002), but was unchanged when expressed per total liver (60.8 +/- 6.5 vs 64.6 +/- 3.5 mumoles/min for clofibrate and controls p greater than 0.5). Irrespective of how it was expressed fatty acid binding protein was significantly increased by the drug treatment. Steady state sulfobromophthalein-glutathione removal velocity was saturable with increasing concentrations of sulfobromophthalein-glutathione in both control and clofibrate-treated livers. Steady state extraction ratio, as well as Vmax and Km for removal, did not differ between the two groups. In keeping with other observations, these data collectively indicate that the hepatic steady state removal of nonmetabolized compounds is not affected by clofibrate.(ABSTRACT TRUNCATED AT 250 WORDS)

'Albumin-receptor' uptake kinetics do not require an intact lobular architecture and are not specific for albumin

When freshly isolated well-stirred single cell suspensions of rat hepatocytes were incubated with 5-600 microM [3H]oleate or [35S]sulfobromophthalein (BSP) in the presence of 150 microM bovine serum albumin (BSA), uptake of both ligands increased as a linear function of the total ligand concentration in the medium. By contrast, when the same ligand concentrations were incubated as 1:1 complexes with BSA, apparent saturation of ligand uptake was observed. Analogous results were obtained in incubations employing beta-lactoglobulin instead of BSA. In none of these studies did ligand uptake velocity correlate in simple fashion with the concentration of unbound ligand in the incubation medium. These studies establish that the basis for the kinetic observations termed the 'albumin receptor phenomenon' does not require an intact hepatic lobular architecture or space of Disse, and is not specific for albumin.

Oleate uptake by cardiac myocytes is carrier mediated and involves a 40-kD plasma membrane fatty acid binding protein similar to that in liver, adipose tissue, and gut

Uptake of [3H]oleate by canine or rat cardiac myocytes is saturable, displays the countertransport phenomenon, and is inhibited by phloretin and trypsin. Cardiac myocytes contain a basic (pI approximately 9.1) 40-kD plasma membrane fatty acid binding protein (FABPPM) analogous to those recently isolated from liver, adipose tissue, and gut, unrelated to the 12-14-kD cytosolic FABP in these same tissues. An antibody to rat liver FABPPM selectively inhibits specific uptake of [3H]oleate by rat heart myocytes at 37 degrees C, but has no influence on nonspecific [3H]oleate uptake at 4 degrees C or on specific uptake of [3H]glucose. Uptake of long-chain free fatty acids by cardiac muscle cells, liver, and adipose tissue and absorption by gut epithelial cells is a facilitated process mediated by identical or closely related plasma membrane FABPs.