Effect of retinal ablation on the expression of calbindin D28k and GABA in the chick optic tectum

The effect of retinal ablation on qualitative and quantitative changes of calbindin D28k and GABA expression in the contralateral optic tectum was studied in young chicks. Fifteen days old chicks had unilateral retinal ablation and after 7 or 15 days, calbindin expression was analyzed by Western blot and immunocytochemistry. Neuronal degeneration was followed by the amino-cupric silver technique. After 15 days, retinal lesions produced a significant decrease in calbindin immunostaining in the neuropil of layers 5-6 and in the somata of neurons from the layers 8 and 10 of the contralateral tectum, being this effect less marked at 7 days post-lesion. Double staining revealed that 50-60% of cells in the layers 8 and 10 were calbindin and GABA positive, 30-45% were only calbindin positive and 5-10% were only GABAergic neurons. Retinal ablation also produced a decrease in the GABA expression at either 7 or 15 days after surgery. At 7 days, dense silver staining was observed in the layers 5-6 from the optic tectum contralateral to the retinal ablation, which mainly represented neuropil that would come from processes of retinal ganglion cells. Tectal neuronal bodies were not stained with silver, although some neurons were surrounded by coarse granular silver deposits. In conclusion, most of calbindin molecules are present in neurons of the tectal GABAergic inhibitory circuitry, whose functioning apparently depends on the integrity of the visual input. A possible role of calbindin in the control of intracellular Ca2+ in neurons of this circuit when the visual transmission arrives to the optic tectum remains to be studied.

[Leflunomide--a new drug for pharmacological immunomodulation]

The novel immunomodulatory agent leflunomide exhibits a strong anti-inflammatory action. This isoxazole derivative is chemically unrelated to any hitherto applied immunosuppressants. As a prodrug leflunomide is completely converted to its active metabolite A 77 1726 (M1) which blocks the dihydroorotate dehydrogenase, a key enzyme of the pyrimidine de novo synthesis. Drug-related adverse effects are mild, dose-related and reversible, characterising leflunomide as a safe immunosuppressant. While up to now leflunomide has just been approved for therapy of rheumatoid arthritis, its mechanism of action affects multiple inflammatory pathways, thereby suggesting it to be a potent therapeutic agent in autoimmune diseases, graft rejection, and tumour therapy. First dermatological experience has been gained in psoriasis and bullous pemphigoid. The role of leflunomide in the dermatologist's therapeutic armamentarium will evolve during the next years.

[Dermatologic steroid therapy during pregnancy and lactation]

Dermatological therapy during pregnancy and lactation should be scrutinized regarding possible side effects for mother or child. Glucocorticoids are a group of agents that have been employed for many years and with appropriate indications and careful monitoring can be used safely and effectively in pregnancy.

Reinforcement of occupational history taking: a success story

BACKGROUND

This article describes the results of a retrospective study of 3 classes of medical students who participated in a targeted occupational and environmental health curriculum at the University of Connecticut School of Medicine.

PURPOSE

We wanted to determine if targeted focused curricular interventions which integrated occupational and environmental health principles into routine history taking would result in increased scores on the number of questions posed during the Clinical Skills Assessment Program in the 4th year.

METHODS

We analyzed Clinical Skills Assessment Program questions for 3 graduating medical school classes from 1997 to 1999.

RESULTS

It appears that intense, focused training may increase the occupational and environmental questions which students ask. By revisiting the components of the history during the 3rd year, the final assessment of 4th-year students substantially and significantly increased.

CONCLUSIONS

Those who wish to stem the decline in history-taking skills as students enter their clinical years should consider reinforcing these skills using structured programs and practice in areas of the history that are traditionally neglected but recognized as essential in gathering comprehensive data on patients.

The variability of serial fMRI data: correlation between a visual and a motor task

We investigated whether the intersession variability of serial fMRI studies correlates between two activation modalities, i.e. a standardized visual and a standardized motor task. Six volunteers were scanned in at least weekly intervals. The number of pixels activated as well as the activation amplitude varied widely. The maximal difference of the number of pixels activated was 1150%, of the activation amplitude 250%. In three volunteers, the variability was highly correlated between the two tasks. Three other volunteers showed one outlier each. We conclude that the intersession variability is due to global factors affecting the whole brain, but that due to unpredictable outliers, using a standardized task to normalize the data of interest is of limited value.

Negative inotropic effects of recombinant interleukin 2 in patients without left ventricular dysfunction

Experimental data have shown that rIL2 has negative inotropic properties. This has not been investigated in humans with normal left ventricular function. Seventeen consecutive renal cell carcinoma patients who received rIL2 therapy because of dissemination were analyzed before and after treatment with a low dose of rIL2 subcutaneously. Left ventricular ejection fraction (echocardiography), heart rate variability parameters (24 h electrocardiography), and TNF alpha, IL1 beta and nitric oxide metabolites (NO(x)) were measured. LVEF decreased from 54+/-7 to 50+/-6% (mean+/-S.D.; P=0.012), with a concomitant increase in heart rate from 87+/-13 to 94+/-13 beats/min (P=0.031). All frequency domain HRV parameters decreased: the total power from 18.0+/-7.9 to 14.0+/-5.0 ms (P=0.001), the low frequency from 10.3+/-5.4 to 8. 3+/-3.4 ms (P=0.001), and the high frequency from 6.3+/-2.6 to 4. 5+/-1.1 ms (P=0.001). There was no measurable effect on TNF alpha, IL1 beta concentrations. Plasma levels of nitrate (NO(x)) increased from 22.8+/-14.4 to 41.8+/-26.6 micromol/l (P=0.007).

CONCLUSIONS

A low dose of rIL2 has a negative inotropic effect that may be mediated by increased NO concentrations. It also reduces sympathetic activity as reflected in HRV parameters.

Decision making of clinical teams: communication patterns and diagnostic error

This study examined the discussion of information among mixed-status clinical teams while constructing differential diagnoses. Twenty-four ad hoc teams, each consisting of a resident, an intern, and a third-year medical student, were given two hypothetical patient cases to discuss and diagnose. Prior to discussion, team members individually viewed different versions of a videotaped interview with a "patient" (trained actor). Each videotape contained some information that was present in all three versions (shared information) and some that was present in only that version (unique information). In addition, half of the time, the cases were constructed so that the unique information that appeared in only one tape was crucial for a correct diagnosis (a "hidden profile" condition). After viewing the videotapes, team members met to discuss the case and develop a differential diagnosis. Discussions were videotaped and analyzed. Overall, shared information was mentioned more often than unique information (p < 0.0001). Furthermore, teams offered incorrect diagnoses significantly more often for hidden-profile cases than for control cases (p < 0.01). The teams' overreliance on previously shared information (inability to appropriately utilize unique information) was detrimental when a correct diagnosis demanded the inclusion of such information. Clinical discussions that require the consideration of uniquely held information may be susceptible to error.

Comparative effects of glimepiride and glibenclamide on blood glucose, C-peptide and insulin concentrations in the fasting and postprandial state in normal man

A single-center, randomised, placebo- controlled, cross-over study was conducted to characterize the new sulfonylurea glimepiride and to compare its profile of action with the second generation sulfonylurea glibenclamide. The total duration of each experiment was 5 hours. At zero time an i.v. injection of 2 and 4 mg glimepiride, 1 mg glibenclamide or placebo was given i.v. to 24 healthy volunteers. Blood samples were collected for three hours after the injection (0-3 hours, preprandial experiment). At 3 hours, a standard mixed meal was given (20%, of a 30 Kcal/Kg Body Weight diet) and blood samples were collected for 2 more hours (postprandial experiment). Pre-prandially (0-3 hrs) blood glucose (expressed as the area under the curve divided by the time) was significantly lower (p < 0.0001) after the administration of 2 and 4 mg glimepiride (3.8 +/- 0.22 and 3.5 +/- 0.3 mM respectively) compared to placebo (4.63 +/- 0.31 mM), but not compared to glibenclamide. Insulin and C-peptide were not different after glimepiride or glibenclamide. Both glimepiride and glibenclamide had similar effects on insulin secretion. Post-prandially (3-5 hrs) blood glucose was significantly higher after glibenclamide (6.54 +/- 0.8 mM) (p < 0.0001) than after 2 mg glimepiride (5.75 +/- 0.5 mM). Despite this C-peptide was significantly higher (p < 0.002) glibenclamide (5.7 +/- 1.5 ng/ml) compared to glimepiride (5.1 +/- 1.3 ng/ml); the trend was the same for insulin but the results were not significantly different (p = 0.06) In conclusion, in the fasting state, glimepiride and glibenclamide had similar effects on the changes in blood glucose levels after i.v. administration. After the meal, less pronounced hyperglycemia and lower insulin and C-peptide levels following glimepiride (2 mg) suggests either that glimepiride induces insulin secretion through a pathway which is different from that of glibenclamide or that glimepiride facilitates insulin action through extrapancreatic effects.

Long-term application of extracorporeal photochemotherapy in severe atopic dermatitis

BACKGROUND

Extracorporeal photochemotherapy (ECP) using UVA irradiation of enriched leukocytes in the presence of methoxsalen as a photoactivatable substrate has been employed for the treatment of several immunologically mediated disorders.

OBJECTIVE

Our purpose was to determine the efficacy and safety of long-term ECP in the treatment of severe atopic dermatitis.

METHODS

Fourteen patients with severe recalcitrant atopic dermatitis were treated with ECP in an open clinical trial at 2-week intervals. Disease activity was scored before each ECP cycle by means of a standardized protocol.

RESULTS

A complete clinical remission was achieved in 4 patients (29%). Five patients (36%) experienced a substantial response with reduction of skin inflammation by at least 75%, whereas in one patient (7%) disease activity was reduced by more than 50%. Four patients were withdrawn from the study for unresponsiveness. No clinical signs of immunosuppression or other severe adverse events became evident.

CONCLUSION

Long-term ECP may have significant beneficial effects on the course of atopic dermatitis and should therefore be considered as a treatment modality for patients suffering from severe and otherwise refractory atopic skin disease.

The rise and fall of students' skill in obtaining a medical history

A gradual shift towards a more humanistic conception of medicine has occurred in recent years. Along with this shift have come attempts by medical educators to include interviewing and communication skills as part of the medical curriculum. The current study evaluates the effectiveness of a clinical medicine curriculum which emphasizes interviewing skills. Between 1992 and 1994 and 292 graduates of the University of Connecticut School of Medicine participated in five clinical skills teaching and assessment programmes during the four years of medical school. During each of these five programmes, the students' interviewing skills were rated using the Arizona Clinical Interview Rating Scale (ACIR). The raters were standardized patients with whom they had just completed a medical encounter. Results show that students' development of skills differed, with closure items showing the greatest increase and social history items showing the greatest decline, with an overall initial increase and then a decline in interviewing skills over the four years. Explanations for these findings include the de-emphasis of communication skills during the clinical years and the culture of medicine to which students are exposed during these years.

SKF 38393 enhances odor detection performance

The purpose of this study was to determine the influence of the D1-selective partial agonist SKF 38393 on the odor detection performance of rats using high precision olfactometry and a go/no-go operant task. Previous studies have found that the D2 receptor partial agonist quinpirole decreases such performance, but the influences of D1 receptor activation are unknown. In experiment 1, such detection performance to the odorant ethyl acetate was enhanced by SKF 38393, relative to saline, in male rats at 7.5 and 10.0 mg/kg i.p. dose levels, but not at the lower doses of 1.0, 2.5, and 5.0 mg/kg. In experiment 2, this enhancement was replicated at the 7.5 and 10.0 mg/kg doses and was shown to occur at the 12.5 mg/kg dose as well. In experiment 3, similar enhancement was shown for the odorant eugenol in female rats at the 7.5, 10.0 and 12.5 mg/kg doses, suggesting this effect is neither sex-specific nor confined to the odorant ethyl acetate. In experiment 4, a 0.025 mg/kg dose of the D1 receptor antagonist SCH 23390 depressed the enhancement produced to ethyl acetate by 7.5 mg/kg SKF 38393 to control levels. Overall, these data demonstrate that, in contrast to quinpirole, SKF 38393 improves odor detection performance in the rat and that this phenomenon can be attenuated by the D1 receptor blocker SCH 23390.

[Childhood and violence: perpetrator and victim perspectives from the viewpoint of criminology]

Police crime statistics show a significant increase in the rates of violent crimes committed by children during the last two years. However, since in Germany children under the age of 14 are not accountable for criminal offences, these statistics are highly selective. On the other hand, police crime statistics also show a huge increase of violent crimes committed by juveniles and young adults which cannot be explained by changes of police intervention strategies. It seems reasonable to attribute this mainly to changed living conditions of young people, particularly the increase proportion of children and adolescents living below the thresholds of poverty. To put the issue of violence and children in perspective, the victimization of children should not be overlooked. Criminological as well as psychological research show the devastating consequences of physical and sexual abuse experiences during childhood. Results of a representative german survey concerning the prevalence of violent victimization experiences during childhood are presented. 13.5% of the male and 16.1% of the female respondents had been victims of severe physical or sexual abuse during childhood. If repeatedly witnessing parental violence is additionally taken into consideration, these rates are 18.3% for male and 20.5% for female respondents. A comparison of age groups failed to identify significant differences of victimization rates, except the rates of minor violence committed by parents. Thus it can be assumed tentatively, that the proportion of children subjected to severe violent acts committed by closely related adults as well as the rate of those witnessing parental violence has remained constant over time.

Chemotherapy for disseminated actinic keratoses with 5-fluorouracil and isotretinoin

BACKGROUND

Disseminated actinic keratoses are a therapeutic problem.

OBJECTIVE

Our purpose was to evaluate the efficacy of a combination of topical 5-fluorouracil twice a day and 20 mg of oral isotretinoin daily for disseminated actinic keratoses.

METHODS

Twenty-seven patients who had disseminated actinic keratoses (3 women, 24 men) were treated with 5-fluorouracil (5%) twice a day applied to the photodamaged area bearing actinic keratoses along with oral isotretinoin, 20 mg daily. The median treatment time was 21 days.

RESULTS

Actinic keratoses disappeared and signs of photodamaged skin improved in all patients. Side effects were burning and itching as well as painful erosions during the final stage of treatment.

CONCLUSION

The combination of topical 5-fluorouracil and isotretinoin is highly effective in the treatment of disseminated actinic keratoses on photodamaged skin.

The effects of acute exercise on metabolic control in type II diabetic patients treated with glimepiride or glibenclamide

The effects of exercise on metabolic control in type II diabetic patients given glimepiride or glibenclamide were studied in a multinational phase II clinical trial (14 centers in 4 countries). A total of 167 type II diabetic out-patients (117 men, 50 women) completed the trial as planned. The study was of parallel group, 2 x 2 factorial design: patients were first stabilized in a randomized, double-blind manner on 3 mg of glimepiride or 10 mg of glibenclamide treatment once daily over 14-28 days and were then assigned in randomized open fashion to a group with or without exercise. Exercise consisted of riding a bicycle ergometer for 1 hour at pulse rate 120 beats per minute. Three-hour blood glucose, insulin, and C-peptide profiles were made after the stabilization phase (baseline profiles) and 7 days later with or without exercise (endpoint profiles). Pairwise comparisons of changes in blood glucose AUC/1-3 h revealed a statistically significant decrease in patients who exercised vs those who did not, which was comparable for both sulfonylureas used. There was a statistically significant decrease in C-peptide AUC/1-3 h and insulin AUC/1-3 h in the glimepiride exercise group vs the glimepiride group without exercise. Physical exercise did not lead to statistically significant changes in C-peptide AUC/1-3 h and insulin AUC/1-3 h under glibenclamide treatment. In conclusion, a blood-glucose-lowering response to acute exercise was demonstrated in type II diabetic patients treated with either sulfonylurea, but a significant suppression of endogenous insulin secretion was observed for glimepiride only.

Polymorphisms of apolipoproteins A-IV and E in a Turkish population living in Germany

Human apolipoproteins (apo) E and apo A-IV are polymorphic with significantly different allele frequencies among different ethnic groups. Whereas the variation at the apo E gene locus affects plasma cholesterol levels in all populations studied so far and is associated with longevity in Caucasians, the influence of the common apo A-IV polymorphism on plasma lipoproteins has not been unanimously accepted. We have therefore determined the common apo E and apo A-IV polymorphisms by isoelectric focusing, calculated the respective allele frequencies and studied their effects on plasma lipoproteins in a random sample of 240 nonrelated Turkish subjects (141 males, 99 females) living in Germany and originating from central and eastern Anatolia. When compared with the German population and other Caucasians in Europe a prominence of the apo epsilon 3 allele frequency (0.885) was accompanied by a decrease in the frequencies of both the apo epsilon 2 allele (0.048) and the apo epsilon 4 allele (0.067). Thus, the Turkish population studied here clustered with populations mainly from southern Europe and Japan, which have low epsilon 2 and epsilon 4 allele frequencies. Also, the frequency of the A-IV-1 allele was higher (0.967) and that of the A-IV-2 allele lower (0.033) in the Turkish subjects studied than in other populations. At an average level of total cholesterol of 194.5 +/- 45 mg/dl, no significant influence of the A-IV alleles on plasma lipoproteins was seen. However, apo E and apo B differed significantly between apo E phenotypes, with high levels of apo E and low levels of cholesterol and apo B in carriers of the epsilon 2 allele, and vice versa for the epsilon 4 allele. The average cholesterol excess for the epsilon 2 allele was -7.95 mg/dl, for the epsilon 3 allele, -1.34, and for the epsilon 4 allele, + 14.15 mg/dl. Thus, despite the unusual frequency distribution of the apo E alleles, their effects on plasma lipoproteins are within the range reported for other populations in Europe.

Extent of T cell receptor ligation can determine the functional differentiation of naive CD4+ T cells

Naive CD4+ T cells can differentiate into cells predominantly involved in humoral immunity, known as T helper type 2 cells (Th2), or cells involved in cell-mediated immunity, known as Th1 cells. In this report, we show that priming of CD4+ T cells bearing a transgene-encoded T cell receptor can lead to differentiation into Th1-like cells producing abundant interferon gamma when the cells are exposed to high antigen doses, while low doses of the same peptide induce cells with the same T cell receptor to differentiate into Th2-like cells producing abundant interleukin 4. Thus antigen dose is one factor that can control the differentiation fate of a naive CD4+ T cell.

Parenteral application of a Pseudomonas aeruginosa flagella vaccine elicits specific anti-flagella antibodies in the airways of healthy individuals

To test the hypothesis that a Pseudomonas aeruginosa flagella (FLA) vaccine, intramuscularly administered, elicits specific antibodies in the respiratory tract, antibody titers against FLA were determined in sera and bronchoalveolar lavage (BAL) fluids of 10 healthy human adults before and after immunization. Immunization produced significantly increased anti-FLA antibody titers in all sera (mean reciprocal titers: IgG: 26,711; IgA: 2,767; IgM: 421) and on respiratory epithelial lining fluids (mean reciprocal titers: IgG: 112; IgA: 76; sIgA: 26). Significant differences in class-specific serum and BAL anti-FLA titers suggested airway antibody production. The study shows that parenteral immunization provides not only high systemic antibody titers but also local antibody production in the human respiratory tract.

Altered peptide ligands can control CD4 T lymphocyte differentiation in vivo

Antigen priming of naive CD4 T cells can generate effector CD4 T cells that produce interleukin 4 (T helper [Th]2-like) or interferon-gamma (Th1-like). Using a system in which priming leads to responses dominated by one or the other of these cell types, we show that varying either the antigenic peptide or the major histocompatibility complex class II molecule can determine whether Th1-like or Th2-like responses are obtained. Our results show that peptide/major histocompatibility complex class II complexes that interact strongly with the T cell receptor favor generation of Th1-like cells, while those that bind weakly favor priming of Th2-like T cells. Thus, signals from the T cell receptor can influence the differentiation of CD4 T cells into specific types of effector cells.

Clozapine therapy for Parkinson's disease and other movement disorders

Recent research on the role of clozapine in the treatment of Parkinson's disease and other movement disorders is discussed. Most clinical trials have shown resolution of or improvement in psychotic symptoms accompanying Parkinson's disease without worsening of parkinsonian symptoms. Adverse effects appear to be mild at dosages of < 100 mg/day; sedation is the most frequent problem. Most of these studies have serious limitations, however; until better studies have been completed, the decision to use clozapine for Parkinson's disease-related psychosis should be made on a case-by-case basis, with thorough evaluation of risks, benefits, and other therapeutic options. Some patients with Parkinson's disease have shown improvement in tremor and other abnormal movements when given clozapine. Clozapine cannot be recommended for treating tardive dyskinesia on the basis of the research done so far; some trials show dramatic resolution of symptoms, others no benefit. Anticholinergics or dopamine-reuptake inhibitors should be considered before clozapine is given to patients with tardive dyskinesia because of clozapine's potential for serious adverse effects. A few patients with Huntington's disease have responded to clozapine, but again no conclusions can be drawn. Clozapine appears to offer no real advantage over haloperidol for treating choreiform movements in Huntington's disease. The frequency of tics in Tourette's syndrome does not seem to be reduced by clozapine. Clozapine has shown some efficacy as a treatment for psychosis and abnormal movements in Parkinson's disease. Results have been less promising for other movement disorders. Further study in larger populations is needed before any definitive conclusions about clozapine's place in movement disorder therapy can be made.

[Dietary folates--a timely review. Stability, physiological significance, bioavailability, analytical determination methods, effect of food handling]

Because of the unequal and, in some instances, low stability of different folate vitamers against extreme conditions the analytical determination of folate and the estimation of folate losses in food processing and preparation cause considerable difficulties. HPLC allows determination of the native folate derivative patterns. As the bioavailability of folates is influenced by a variety of factors and different methods were employed for assessing bioavailability there is a considerable inconsistency in the results of these studies. Folates labeled with radioactive or stable isotopes provide new approaches to metabolic and bioavailability studies.

Major histocompatibility complex (MHC) control of CD4 T cell subset activation. II. A single peptide induces either humoral or cell-mediated responses in mice of distinct MHC genotype

CD4 T cells activated in vivo in response to human collagen type IV (hCol IV) resemble either T helper type 1 (Th1) or Th2 cells depending on the major histocompatibility complex (MHC) class II genotype of the responding mice. H-2s mice were shown to selectively activate Th1-like cells, releasing interleukin (IL 2 and interferon-gamma in response to hCol IV, whereas H-2b.d mice were shown to selectively activate Th2-like cells, releasing IL 4 and IL 5 in response to hCol IV. These results suggested that MHC class II regulated the type of effector function observed during an immune response. It was of interest to determine if the functional difference observed between the CD4 T cells of the two strains was due to the presentation of different peptides of the hCol IV molecule by the two MHC class II molecules. The present results demonstrate that a single peptide of the collagen IV molecule will elicit a Th1-like response in H-2s strains and Th2-like responses in H-2b.d strains, as was observed when using the intact hCol IV molecule. Furthermore, the failure to generate Th1-like responses in H-2b.d could be overcome by increasing the dose of this peptide in vitro. Compared to H-2s, the Th1-like response in H-2b required 100 times the amount of peptide to reelicit an equivalent response. These data suggest that a single peptide of hCol IV can control the type of effector response observed.

Bilateral olfactory dysfunction in early stage treated and untreated idiopathic Parkinson's disease

Decreased olfactory function is among the first signs of idiopathic Parkinson's disease (PD). Whether such dysfunction is present to the same degree on both sides of the nose, however, is unknown. Furthermore, whether the deficit results from or is influenced by anti-Parkinsonian medications has not been definitely established. Odour identification ability was evaluated on the left and right sides of the nose in 20 early-stage untreated PD patients, 20 early-stage treated PD patients, and 20 controls. In all cases, the PD related olfactory dysfunction was bilateral and no difference was observed between the test scores of patients taking or not taking drugs for PD. Although asymmetries of unsystematic direction were present in the test scores of some PD patients, similar asymmetries were observed in the controls and the asymmetries were not related to the side of the major motor dysfunction. As in earlier work, no relation was present between the olfactory test scores and the degree of tremor, rigidity, bradykinesia, or gait disturbance at the time of testing. These findings indicate that the olfactory dysfunction of early stage PD is robust, typically of the same general magnitude on both sides of the nose, and uninfluenced by anti-Parkinsonian medications.

Characterization of an isoelectric focusing variant of SAA1 (ASP-72) in a family of Turkish origin

An acidic variant of serum amyloid A (SAA) identified previously by isoelectrofocusing in a family of Turkish origin has been characterized at the genomic level. DNA sequence analysis revealed that individuals expressing the variant pI6.1/pI5.7 isoforms (the mother and three of four children) were heterozygous at the SAA1 gene locus. Their SAA1 gene sequences contained an adenine, as well as the usual guanine, at the position corresponding to the second base of codon 72. The presence of both bases predicts two SAA1 protein sequences, one having aspartic acid and the other glycine at position 72. While the Gly-72 SAA1 (+/- Arg-1) sequence represents the normal pI6.5/pI6.0 isoforms, the Asp-72 SAA1 (+/- Arg-1) sequence corresponds to the variant pI6.1/pI5.7 isoforms.