[Quality specifications and allowable standards for validation of methods used in clinical biochemistry]

The purpose of this work is to provide, for a large number of analysis in the field of clinical biochemistry, appropriate criteria for the evaluation of the performance of in vitro diagnostic methods. Based on a first set of data established in 1986 and the experience cumulated by organisers in charge of internal and external quality assessment surveys, an expert group has proposed acceptable limits for a large list of analysis (n = 116). Data are reported and presented in tables divided into 7 chapters including: general biochemistry, enzymes, proteins, tumour markers, hormones, drugs (and toxic), and urinary analysis. For each analysis are given: analytical and reference ranges, three concentration levels for control specimens to be used during evaluations and the range of values within which they can be chosen, reproducibility and repeatability limits expressed as CV%. Maximal tolerable systematic error and inaccuracy are given for control and biological specimens and compared to those obtained using a reference or validated method. These data are essential for evaluations using the protocol designed by the SFBC and can serve as quality criteria for the choice and validation of in vitro diagnostic systems.

Factors contributing to physicians' success in the advanced trauma life support program in Israel

BACKGROUND

Since its introduction in Israel, more than 4,000 physicians from various specialties and diverse medical backgrounds have participated in the Advanced Trauma Life Support course.

OBJECTIVES

To analyze the factors that influence the success of physicians in the ATLS written tests.

METHODS

A retrospective study was conducted of 4,475 physicians participating in the Israeli ATLS training program between 1990 and 1996. Several variables in the records of these physicians were related to their success or failure in the final written examination of the course.

RESULTS

Age, the region of medical schooling, and the medical specialty were found to significantly influence the successful completion of the ATLS course.

CONCLUSIONS

Physicians younger than 45 years of age or with a surgical specialty are more likely to graduate the ATLS course. The success rate could be improved if the program's text and questionnaires were translated into Hebrew.

Effects of an amino acid dialysate on leucine metabolism in continuous ambulatory peritoneal dialysis patients

BACKGROUND

Protein-energy malnutrition is frequent in continuous ambulatory peritoneal dialysis (CAPD) patients. The use of amino acids in the dialysate could improve the protein balance, especially if associated to a concomitant energy intake.

METHODS

A 1.1% amino acid solution for peritoneal dialysis was administered to CAPD patients over 30 minutes during concomitant absorption of 600 ml water (control study) or of a 600 kcal meal/600 ml. Leucine metabolism was studied using the combination of intravenous [2H3] and intraperitoneal [13C] leucine.

RESULTS

The rate of leucine appearance was stimulated by 56 and 53% (control and meal) at 45 minutes. The rates of leucine appearance and disappearance were lower from 180 to 300 minutes during the meal versus control study (P < 0.05). Proteolysis was unaffected during the control study and was inhibited by 25% during the meal study (P < 0.05). During the five-hour cycle dialysis with or without a meal, 80% of the leucine administered into the peritoneum was absorbed. Forty-one percent was retained in the splanchnic bed. Forty-three percent was used for protein synthesis, and 16% was oxidized.

CONCLUSIONS

This amino acids solution is efficaciously utilized for protein synthesis in CAPD patients with no effect on protein breakdown. The concomitant ingestion of a carbohydrate-lipid meal inhibits protein breakdown and reinforces a positive effect of the amino acids solution on protein balance.

Clinical implications of fluorescence in situ hybridization analysis in 13 chronic myeloid leukemia cases: Ph-negative and variant Ph-positive

Thirteen chronic myeloid leukemia (CML) patients, 10 with variant Philadelphia (Ph) translocations and 3 Ph negative cases, were analyzed by fluorescence in situ hybridization (FISH) with the use of BCR and ABL cosmid probes and a chromosome 22 painting probe. In the variant Ph translocations, the BCR-ABL fusion gene was located on the Ph chromosome; in 1 CML Ph-negative patient, the BCR-ABL fusion gene was located on the Ph chromosome; and, in 2 patients, it was located on chromosome 9. The chromosome 22 painting probe was detected on the third-party chromosome of the variant translocation, and in none of the variant translocations was there any detectable signal on chromosome 9. In CML patients with clonal evolution of a simple Ph, a signal of the chromosome 22 painting probe was detected on the der(9) of the Ph translocation. It was concluded that the variant Ph translocations evolved simultaneously in a three-way rearrangement. The clinical parameters of the 13 patients were similar to those of a large group of CML patients with a simple Ph translocation. It is suggested that, to determine the prognosis of CML patients with a complex karyotype, FISH analysis with a chromosome 22 painting probe be performed.

The type 2 family: a setting for development and treatment of adolescent type 2 diabetes mellitus

OBJECTIVE

To identify physical, behavioral, and environmental features of adolescents (aged 11-17 years) with type 2 diabetes mellitus and their families to define the involvement of known risk factors and to define a profile of at-risk individuals.

DESIGN AND METHODS

A total of 42 subjects from 11 families with an adolescent in whom type 2 diabetes was previously diagnosed participated. All subjects underwent anthropometric measurement and completed food frequency and eating disorder questionnaires, and were classified according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. In addition, laboratory tests to determine levels of hemoglobin A1c, fasting glucose, C peptide, insulin, and proinsulin were performed.

RESULTS

Type 2 diabetes had been diagnosed in 5 of 11 mothers and 4 of 11 fathers before the study. Type 2 diabetes was diagnosed in 3 of the remaining 7 fathers during the study. In 3 families, both parents were affected with type 2 diabetes. As a group, participants were obese, with a body mass index higher than the 95th percentile for probands and fathers, and higher than the 85th percentile for mothers and siblings. The sum of skin fold measurements was above the 95th percentile for the probands, their siblings, and the parents. All groups had high fat intake and low fiber intake. None of the subjects participated in a structured or routine exercise program, and most reported no regular physical activity. Three of the probands met the criteria for binge-eating disorder, and 6 additional patients had notable characteristics of the disorder. Mothers affected with type 2 diabetes had markedly abnormal hemoglobin A1c levels, indicating poor control. There were no group differences in fasting concentrations of insulin, proinsulin, or C peptide. However, a third of the mothers with type 2 diabetes, and all but 1 of the siblings, had evidence of insulin resistance.

CONCLUSIONS

Adolescents in whom type 2 diabetes has been diagnosed, as well as their first-degree family members, are obese. In addition, the incidence of diagnosed and undiagnosed type 2 diabetes or of insulin resistance in the families of adolescents with type 2 diabetes is striking. Probands and other family members have lifestyles characterized by high fat intake, minimal physical activity, and a high incidence of binge eating. These findings indicate that the families of adolescents with type 2 diabetes share many anthropometric and lifestyle risk factors. The design of treatment programs for adolescents with type 2 diabetes will need to address the lifestyle and health habits of the entire family.

Successful endoscopic drainage of a posttraumatic pancreatic pseudocyst in a child

The successful endoscopic drainage of a posttraumatic pancreatic pseudocyst in a 9-year-old boy is described. This case study suggests that there is a role for endoscopic placement of stents in the treatment of pancreatic pseudocysts in children.

Acute hyperphosphatemia caused by sodium phosphate enema in a patient with liver dysfunction and chronic renal failure

We report a case of acute hyperphosphatemia secondary to rectal administration of sodium phosphate and sodium biphosphate (Fleet enema). Parathyroid hormone and calcitonin levels were measured along with phosphate clearance and the tubular reabsorption of phosphate.

Alteration of the leptin network in late morbid obesity induced in mice by brain infection with canine distemper virus

Viruses can induce progressive neurologic disorders associated with diverse pathological manifestations, and therefore, viral infection of the brain can impair differentiated neural functions, depending on the initial viral tropism. We have previously reported that canine distemper virus (CDV) targets certain mouse brain structures, including the hypothalamus, early and selectively. Infected mice exhibit acute encephalitis, with late disease, characterized by motor impairment or obesity syndrome, appearing in some of the surviving mice several months after the initial viral replication. In the present study, we show viral persistence in the hypothalami of obese mice, as demonstrated by low, but still significant, levels of CDV nucleoprotein transcripts, associated with a dramatic decrease in F gene mRNAs. Given the pivotal role of the hypothalamus in obesity (eating behavior, energy consumption, and neuroendocrine function) and that of leptin, the adipose tissue-derived satiety factor acting through hypothalamic receptors, we analyzed the leptin networks in both obese and nonobese mice. The discrepancy found between the chronic and dramatic increase in blood leptin levels and the occurrence of obesity may be due to leptin resistance in the brain. In fact, expression of the long leptin receptor isoform, representing the functional leptin receptor, was specifically downregulated in the hypothalami of obese mice, explaining their inability to generate an adequate response to leptin in the brain. Intriguingly, during the acute phase of infection, its expression was increased in CDV-targeted structures in all infected mice and remained high in obese mice in all CDV-targeted structures, except for the hypothalamus. The biphasic change in hypothalamic leptin receptor expression seen during the progression of CDV-induced obesity provides a new paradigm for understanding mechanisms of neuroendocrinological, virus-induced abnormalities.

Hospital peer review and the National Practitioner Data Bank: clinical privileges action reports

CONTEXT

The National Practitioner Data Bank (NPDB) is believed to be an important source of information for peer review activities by the majority of those who use it. However, concern has been raised that hospitals may be underreporting physicians with performance problems to the NPDB.

OBJECTIVE

To examine variation in clinical privileges action reporting by hospitals to the NPDB, changes in reporting over time, and the association of hospital characteristics with reporting.

DESIGN

Retrospective cohort study of privileges action reports to the NPDB between 1991 and 1995, linked with the 1992 and 1995 databases from the Annual Survey of Hospitals conducted by the American Hospital Association.

SETTING AND PARTICIPANTS

A total of 4743 short-term, nonfederal, general medical/surgical hospitals throughout the United States that were continuously open between 1991-1995 and registered with the NPDB.

MAIN OUTCOME MEASURES

(1) Reporting of 1 or more privileges actions during the 5-year study period and (2) privileges action reporting rates (numbers of actions reported per 100000 admissions).

RESULTS

Study hospitals reported 3328 privileges actions between 1991 and 1995; 34.2% reported 1 or more actions during the period. The range of privileges action reporting rates for these hospitals was 0.40 to 52.27 per 100000 admissions, with an overall rate of 2.36 per 100000 admissions. The proportion of hospitals reporting an action decreased from 11.6% in 1991 to 10.0% in 1995 (P=.008). After adjustment for other factors, urban hospitals had significantly higher reporting than rural hospitals (adjusted odds ratio [OR], 1.21 [95% confidence interval [CI], 1.02-1.43]), while members of the Council of Teaching Hospitals of the Association of American Medical Colleges had significantly lower reporting than nonmembers (adjusted OR, 0.54 [95% CI, 0.40-0.73]). There were notable regional differences in reporting, with the east south Central region having the lowest rate per 100000 admissions (1.49 [95% CI, 1.33-1.65]).

CONCLUSIONS

The results of this study indicate a low and declining level of hospital privileges action reporting to the NPDB. Several potential explanations exist, 1 of which is that the information reported to the NPDB is incomplete.

Switch to non-CFC inhaled corticosteroids: a comparative efficacy study of HFA-BDP and CFC-BDP metered-dose inhalers

Inhaled corticosteroids, such as beclomethasone dipropionate (BDP), recommended for the treatment of persistent, mild, moderate, or severe asthma, have traditionally been administered via chlorofluorocarbon (CFC) propellant. The imminent phasing out of CFCs from pharmaceutical preparations due to the Montreal Protocol means patients will have to switch to a CFC-free alternative. One such preparation is hydrofluoroalkane-BDP (HFA-BDP), a press-and-breathe metered-dose inhaler. This 8-week, open-label, multicentre study assessed asthma control in patients switching from CFC-BDP to HFA-BDP (QVAR). Patients with asthma, stabilised on 400-1600 micrograms/day CFC-BDP, were randomised to HFA-BDP (354 patients; 75%) at half their current daily dose of CFC-BDP, or to CFC-BDP (119 patients; 25%). HFA-BDP efficacy was found to be equivalent to that of CFC-BDP in that no statistically significant difference was observed between the two groups in the mean change from baseline in a.m. PEF (95% CI within +/- 11 l/min). No statistically significant differences were observed between the two groups for increased asthma symptoms or acute asthma episodes. We conclude that asthma control was maintained over 8 weeks, with few asthma exacerbations, in patients switching from previous CFC-BDP therapy to HFA-BDP at half the dose.

Colloidal Protein Solutions as a New Standard Sensor for Adhesive Wettability Measurements

Wetting experiments are carried out for the investigation of the interfacial interactions that take place when various solid materials are in contact with protein colloidal solutions. These materials are chosen because they are widely used in the field of orthopedic surgery. Contact angles (sessile drop) and surface tension (du Nouy's ring method) are measured in standardized conditions which take into account the various parameters disturbing wetting phenomena. An original cumulative deposits method (CDM) described here permits observation of the evolution of the wettability and allows estimation of the protein adhesion rate. Two families of materials emerge according to their behavior when they are in contact with the protein solution. One set (a chromium cobalt alloy and two polyethylenes) presents no detectable adhesion. The other set (stainless steel, zirconia, alumina, virgin and nitrogen implanted titanium alloy) shows a cumulative adhesion of proteins. We propose to adopt a BSA buffered solution as a referential sensor to characterize solid surfaces. From the CDM, the practical parameter P*, called the adhesive wettability power, can be used in order to analyze and classify biomaterials. Copyright 1999 Academic Press.

One dose ceftriaxone vs. ten days of amoxicillin/clavulanate therapy for acute otitis media: clinical efficacy and change in nasopharyngeal flora

OBJECTIVE

To compare the efficacy and the safety of a single intramuscular dose of ceftriaxone, 50 mg/kg, vs. a 10-day course of amoxicillin/clavulanate (amox/clav) therapy, 80 mg/kg/day of amoxicillin: 10 mg/kg/day of clavulanate in three divided doses, in children with acute otitis media (AOM) and to evaluate the changes in nasopharyngeal flora after treatment.

METHODS

In a prospective, comparative, open randomized, multicenter trial, children were scheduled to return for visits on Days 12 to 14 (main end point) and Days 28 to 42 after the beginning of treatment for AOM. A nasopharyngeal swab for bacterial culture was obtained before the treatment and at Days 12 to 14.

RESULTS

Between February, 1995, and May, 1996, 513 children with a mean age of 14.2 +/- 6.7 months were enrolled. All the patients were evaluable for the safety and intent-to-treat analyses and 463 for the per protocol efficacy. At Days 12 to 14 clinical success was obtained in 186 of the 235 children (79%) given ceftriaxone and in 188 of the 228 children (82.5%) treated with amox/clav. Among the patients with clinical success on Days 12 to 14, the success was maintained at Days 28 to 42 for 108 of 183 (59%) patients in the ceftriaxone group and 103 of 187 (55%) patients in the amox/clav group. Before the antibiotic treatment the percentages of children carrying Streptococcus pneumoniae (59.1%), Haemophilus influenzae (39.4%), Moraxella catarrhalis (55.7%) and the rate of penicillin-resistant S. pneumoniae (52.2%) were comparable between the 2 groups. At Days 12 to 14 the carriage of S. pneumoniae and M. catarrhalis was significantly different between the patients treated with ceftriaxone, 43.9 and 42.2, respectively, and the patients treated with amox/clav, 17.4 and 11.1%, respectively. Among the children carrying S. pneumoniae at Days 12 to 14, the percentage of penicillin-resistant strains reached 63.4% in the ceftriaxone treatment group and 83.0% in the amox/clav treatment group, (P = 0.02). Adverse events (mainly diarrhea) related to the study medication were reported more frequently (P < 0.0001) in the amox/clav treatment group.

CONCLUSIONS

In an area with a high rate of penicillin-resistant S. pneumoniae, a single dose of ceftriaxone is as efficient as a 10-day course of amox/clav in the treatment of AOM in young children. There was for the two regimens an increased rate of penicillin-resistant strains among the pneumococci carried, whereas the chance for a child to carry a penicillin resistant S. pneumoniae did not increase after treatment.

Ipratropium bromide nasal spray 0.03% and beclomethasone nasal spray alone and in combination for the treatment of rhinorrhea in perennial rhinitis

BACKGROUND

Perennial rhinitis is a common condition that affects up to 10% to 20% of the population. Multiple agents are frequently administered since no single agent provides complete relief. Studies assessing the benefit/risk of combined therapy are important especially for newly approved agents such as ipratropium bromide nasal spray 0.03%, a topical anticholinergic agent, approved specifically for the treatment of rhinorrhea in allergic and non-allergic perennial rhinitis.

OBJECTIVE

To compare the efficacy and safety of the combined use of ipratropium bromide nasal spray 0.03% (42 microg per nostril tid) and beclomethasone dipropionate nasal spray (84 microg per nostril bid) against that of either active agent alone for the treatment of rhinorrhea.

DESIGN

Multicenter, 6-week, double-blind, randomized active- and placebo-controlled, parallel trial.

SETTING

Allergist and general practitioner clinical practices.

PATIENTS

Five hundred thirty-three patients with perennial rhinitis (279 allergic and 274 non-allergic), 8 to 75 years of age, who had at least a mild degree of severity of rhinorrhea for a minimum of 2 hours per day during the 1 week screening period as well as congestion or sneezing also of at least mild severity.

INTERVENTION

Either (1) ipratropium bromide nasal spray 0.03% (42 microg per nostril tid) plus beclomethasone dipropionate nasal spray (84 microg per nostril bid), (2) ipratropium bromide nasal spray 0.03% (42 microg per nostril tid) alone, (3) beclomethasone dipropionate nasal spray (84 microg per nostril bid) alone, or (4) vehicle [matching placebo nasal spray for the ipratropium bromide (2 sprays per nostril tid)] or beclomethasone dipropionate (2 sprays per nostril bid).

MAIN OUTCOME MEASURE

Severity and duration of rhinorrhea, and patient and physician global assessment of control of rhinorrhea.

RESULTS

Ipratropium bromide nasal spray plus beclomethasone nasal spray was more effective than either active agent alone or vehicle in reducing the average severity and duration of rhinorrhea during 4 weeks of treatment. The advantage of ipratropium bromide plus beclomethasone nasal spray was evident by the first day of combined treatment and continued throughout the 2-week treatment period. Ipratropium bromide nasal spray had a faster onset of action during the first week of treatment and reduced the duration of rhinorrhea more than beclomethasone. Beclomethasone nasal spray was more effective in reducing the severity of congestion and sneezing than ipratropium. In patients who had not responded well to a nasal steroid prior to participation in the study based on a questionnaire administered at screening, ipratropium bromide was as effective in the steroid non-responders as steroid responders, whereas beclomethasone was more effective in steroid responders. Combined active therapy was well tolerated with no increase in adverse events over that seen previously with ipratropium bromide or beclomethasone nasal spray alone.

CONCLUSIONS

The combined use of ipratropium bromide nasal spray with beclomethasone dipropionate nasal spray is more effective than either active agent for the treatment of rhinorrhea, and does not result in a potentiation of adverse drug reactions. Ipratropium bromide nasal spray 0.03% alone should be considered in patients for whom rhinorrhea is the primary symptom, and its use in combination with a nasal steroid should be considered in patients where rhinorrhea is one of the predominant symptoms, or in patients with rhinorrhea not fully responsive to other therapy.

Event-related potential correlates of proactive interference in schizophrenic patients and controls

Performance and event-related potentials (ERPs) were examined in a proactive interference (PI) task with 15 male schizophrenic patients and 15 matched healthy controls. Within a paired-associate task, 30 pairs of semantically unrelated words (A-B) were presented twice, followed by cued recall, in which the paired-associate B had to be named upon cue A. Subsequently, 50% of the A-words were paired with new words (A-C) and presented in random order together with 15 novel pairings (D-E). Slower responses and poorer recall of C- than of E-words in the final recall indicated PI in both groups. During acquisition, the paired-associates (C/E) evoked larger P3 and positive slow wave in controls than in patients. During recall, cues (A/D) evoked a slow wave with predominating anterior negativity in controls and posterior positivity in patients. The group-specific ERP pattern suggests deviant encoding and retrieval processes in schizophrenic individuals.

Randomized phase II study of BR96-doxorubicin conjugate in patients with metastatic breast cancer

PURPOSE

BMS-182248-1 (BR96-doxorubicin immunoconjugate) is a chimeric human/mouse monoclonal antibody linked to approximately eight doxorubicin molecules. The antibody is directed against the Lewis-Y antigen, which is expressed on 75% of all breast cancers but is limited in expression on normal tissues. Preclinical xenograft models demonstrated significant antitumor activity, including cures. A randomized phase II design was chosen to estimate the activity of the BR96-doxorubicin conjugate in metastatic breast cancer in a study population with confirmed sensitivity to single-agent doxorubicin.

PATIENTS AND METHODS

Patients with measurable metastatic breast cancer and immunohistochemical evidence of Lewis-Y expression on their tumor received either BR96-doxorubicin conjugate 700 mg/m2 IV over 24 hours or doxorubicin 60 mg/m2 every 3 weeks. Patients were stratified on the basis of prior doxorubicin exposure, visceral disease, and institution. Cross-over to the opposite treatment arm was allowed with progressive or persistently stable disease.

RESULTS

Twenty-three patients who had received a median of one prior chemotherapy regimen were assessable. There was one partial response (7%) in 14 patients receiving the BR96-doxorubicin conjugate and one complete response and three partial responses (44%) in nine assessable patients receiving doxorubicin. No patient experienced a clinically significant hypersensitivity reaction. The toxicities were significantly different between the two treatment groups, with the BR96-doxorubicin conjugate group having limited hematologic toxicity, whereas gastrointestinal toxicities, including marked serum amylase and lipase elevations, nausea, and vomiting with gastritis, were prominent.

CONCLUSION

The BR96-doxorubicin immunoconjugate has limited clinical antitumor activity in metastatic breast cancer. The gastrointestinal toxicities likely represent binding of the agent to normal tissues expressing the target antigen and may have compromised the delivery of the immunoconjugate to the tumor sites.

Lupron-induced mania

BACKGROUND

Gonadotropins and sex hormones are intimately related to the stability of affective states. Patients with affective disorders may demonstrate abnormal levels of sex hormones and gonadotropins. It is therefore possible that affective disorder patients may experience mood dysregulation by synthetic sex hormones and gonadotropins like lupron.

METHODS

A case report of a young woman with a history of endometriosis and a past history of irritability and depression is described. Treatment of the endometriosis with lupron induced a manic episode.

RESULTS

The lupron-induced mania was successfully treated with a mood-stabilizing agent, lithium carbonate.

CONCLUSIONS

Patients with a history of affective disorder may develop manic episodes when treated with Lupron. Mood-stabilizing agents are helpful in ameliorating this unwanted effect.

The naming deficit in early Alzheimer's and vascular dementia

Patients with early Alzheimer's disease (AD) were compared to normal controls and patients with early vascular dementia (VaD) on their naming errors using the Boston Naming Test (H. Goodglass & E. Kaplan, 1983). All naming errors were classified into three general error categories: visuoperceptual, semantic, and phonemic. Semantic errors were further classified into coordinate errors (responses that belong to the same semantic category as the target words), superordinate errors (responses that belong to a broader semantic category than the target word), and functional-circumlocutory errors (circumlocutions and responses that functionally describe the target word). The findings indicated that AD participants display more overall naming errors than VaD participants, although the pattern of general errors was similar between the patient groups. However, the qualitative difference between the patient groups was observed within the semantic errors because the AD group made more superordinate errors.

Differential actions of the dopamine agonist bromocriptine on growth of SMtTW tumors exhibiting a prolactin and/or a somatotroph cell phenotype: relation to dopamine D2 receptor expression

Dopamine (Da) and Da agonists are known to inhibit secretion and proliferation of normal and tumoral PRL cells, through receptors of D2 subtype. Because of the lack of an experimental model, the relationship between bromocriptine (BR) sensitivity and D2 receptor expression is poorly documented. Such a relationship was analyzed using five lineages of spontaneous transplantable rat pituitary tumors (SMtTW) exhibiting different PRL/GH phenotypes. From plasma PRL and GH concentrations of rats bearing the tumors and tumor messenger RNA contents, tumors were classified as PRL (SMtTW2), somatotroph (SMtTW10), or somatomammotroph (SMtTW5) tumors. Two lineages (SMtTW3 and SMtTW4) represented variants producing PRL and GH but with a high predominance of PRL. With the exception of SMtTW4 tumors, which were malignant, all the tumors were benign and differed in their growth rate. Hormone production and growth of tumors with a PRL or a somatomammotroph phenotype were reduced by about 90% under BR treatment, whereas somatotroph tumors and the PRL malignant tumors were totally insensitive to BR. D2 receptor messenger RNA was present in all BR-sensitive tumors and was not detected in BR-resistant tumors. In conclusion, using five lineages of SMtTW tumors that are representative of the most frequent tumors encountered in human pituitary pathology, we found a full concordance between tumor responses to BR and the expression of D2 receptor by the tumors. The identification of a tumor lineage with a malignant phenotype, secreting high amounts of PRL and presenting a resistance to BR, supports the idea that Da-resistant prolactinomas are aggressive tumors.