Low medical morbidity and mortality after acute courses of electroconvulsive therapy in a population-based sample

BACKGROUND

To determine event rates for specific medical events and mortality among individuals receiving electroconvulsive therapy (ECT).

METHOD

Population-based cohort study using health administrative data of acute ECT treatments delivered in Ontario, Canada, from 2003 to 2011. We measured the following medical event rates, per 10 000 ECT treatments, up to 7 and 30 days post-treatment: stroke, seizure, acute myocardial infarction, arrhythmia, pneumonia, pulmonary embolus, deep vein thrombosis, gastrointestinal bleeding, falls, hip fracture, and mortality.

RESULTS

A total of 135 831 ECT treatments were delivered to 8810 unique patients. Overall medical event rates were 9.1 and 16.8 per 10 000 ECT treatments respectively. The most common medical events were falls (2.7 and 5.5 per 10 000 ECT treatments) and pneumonia (1.8 and 3.8 per 10 000 ECT treatments). Fewer than six deaths occurred on the day of an ECT treatment. This corresponded to a mortality rate of less than 0.4 per 10 000 treatments. Deaths within 7 and 30 days of an ECT treatment, excluding deaths due to external causes (e.g., accidental and intentional causes of death), were 1.0 and 2.4 per 10 000 ECT treatments respectively.

CONCLUSION

Morbidity and mortality events after ECT treatments were relatively low, supporting ECT as a low-risk medical procedure.

An international study of the quality of national-level guidelines on driving with medical illness

BACKGROUND

Medical illnesses are associated with a modest increase in crash risk, although many individuals with acute or chronic conditions may remain safe to drive, or pose only temporary risks. Despite the extensive use of national guidelines about driving with medical illness, the quality of these guidelines has not been formally appraised.

AIM

To systematically evaluate the quality of selected national guidelines about driving with medical illness.

DESIGN

A literature search of bibliographic databases and Internet resources was conducted to identify the guidelines, each of which was formally appraised.

METHODS

Eighteen physicians or researchers from Canada, Australia, Ireland, USA and UK appraised nine national guidelines, applying the Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument.

RESULTS

Relative strengths were found in AGREE II scores for the domains of scope and purpose, stakeholder involvement and clarity of presentation. However, all guidelines were given low ratings on rigour of development, applicability and documentation of editorial independence. Overall quality ratings ranged from 2.25 to 5.00 out of 7.00, with modifications recommended for 7 of the guidelines. Intra-class coefficients demonstrated fair to excellent appraiser agreement (0.57-0.79).

CONCLUSIONS

This study represents the first systematic evaluation of national-level guidelines for determining medical fitness to drive. There is substantive variability in the quality of these guidelines, and rigour of development was a relative weakness. There is a need for rigorous, empirically derived guidance for physicians and licensing authorities when assessing driving in the medically ill.

Reduced GLP-1R expression in gastric glands of patients with type 2 diabetes mellitus

BACKGROUND

The incretin effect is reduced in type 2 diabetes mellitus (T2DM) patients. Whether the impaired function of the enteropancreatic axis in these patients is due to defective GLP-1 receptor (GLP-1R) expression in extrapancreatic target organs is not known.

AIMS AND METHODS

To compare the GLP-1R expression and distribution in gastric mucosa biopsies of patients with (n =22) and without (n =22) T2DM referred for routine esophagogastroduodenoscopies. GLP-1R mRNA levels were estimated by real-time PCR. The intensity of GLP-1R immunostaining, frequency, and types of glandular cells bearing GLP-1R and their glandular distribution in different stomach mucosa regions were evaluated by immunohistochemical morphological semiquantitative and quantitative analysis.

RESULTS

Mean mRNA GLP-1R levels were significantly reduced in patients with T2DM compared with nondiabetic patients (P < .02). Immunohistochemical analysis revealed that the reduced GLP-1R expression in T2DM patients was due to a decreased intensity of immunostaining (P < .01). The number of glandular GLP-1R-bearing cells in both body and antrum mucosa was decreased in T2DM patients. Most notably, the frequency of GLP-1R immunoreactive acid-secreting parietal cells was reduced in the neck area of the gastric principal glands of T2DM patients (P < .01). No correlation was found between the reduced GLP-1R expression and clinical parameters including body mass index, age, glycosylated hemoglobin, and disease duration.

CONCLUSION

This is the first evidence of reduced GLP-1R expression in gastric glands of T2DM patients. These data demonstrate that the defective function of the incretin axis in T2DM may also result from decreased GLP-1R expression in its extrapancreatic target organs.

Constitutive abnormal expression of RasGRP-1 isoforms and low expression of PARP-1 in patients with systemic lupus erythematosus

OBJECTIVE

Defective expression of Ras guanil releasing protein-1 (RasGRP-1) and increased apoptosis have been reported in lymphocytes from SLE patients. Whether these aberrations are correlated and linked to disease activity has not been elucidated.

METHODS

Expression of normal 90 kDa RasGRP-1, its most prevalent 86 kDa isoform and full PARP-1 116 kDa and its cleavage fragment 84 kDa were determined in whole protein lysates of peripheral blood mononuclear cells (PBMC) in correlation with mitogen activated protein kinase (MAPK) activity and SLE clinical status in a large group of SLE patients during 1 year follow-up.

RESULTS

Expression of normal 90 kDa RasGRP-1 was comparable in patients and controls. However, SLE patients demonstrated a constitutively increased 86 kDa/90 kDA ratio (p < 0.01) and decreased full poly (ADP-ribose) polymerase protein-1 (PARP-1) expression (p < 0.002) compared with controls who were disease-independent. A remission in disease activity was associated with decreased RasGRP-1 expression. Expression of 84 kDa PARP-1 cleavage fragment was found in 15% of patients but in none of the controls. In addition, expression of PARP-1 correlated positively with normal 90 kDa RasGRP-1 expression and negatively with the RasGRP-1 86 kDa/90 kDA ratio.

CONCLUSIONS

These data suggest that constitutive aberrant expression of PARP-1 and RasGRP-1 ratio may act in concert to impair survival of lymphocytes in SLE patients.

Comparison of modified preadmission glucose-lowering regimen with basal/bolus regimen for glucose control on outcome in general medicine wards

BACKGROUND

It is undecided whether glucose control as advocated by the professional organisations and the glucose-lowering method by itself affects clinical outcome in patients with diabetes mellitus hospitalised in general medical wards. Our aim was to investigate whether a basal/bolus regimen and a modified prehospitalisation regimen have a different impact on the clinical diabetic patients in general medicine wards.

METHODS

Glucose control of patients with diabetes hospitalised in two different wards of internal medicine was achieved according to their wards' policy: a modified preadmission regimen (conventional regime) or a basal/bolus regimen (intensive regime). Death and any adverse event were determined during hospitalisation and within 6 months after discharge to assess clinical outcome.

RESULTS

Median fasting and daily glucose levels were similar in the conventional (n = 116) and intensive regime (n = 129) groups: 161 mg/dl (inter-quartile range: 138-201) and 176 mg/dl (152-215) vs. 155 mg/dl (133-208) and 173 mg/dl (146-208) respectively. Clinical outcome was not affected by the treatment modality. In the subgroup of patients hospitalised with infection, the median fasting glucose was significantly lower in the interventional compared with the conventional regime: 141 and 172 mg/dl respectively (p = 0.041). However, tighter control was associated with a significantly higher incidence of adverse events within 6 months after discharge: 48.9% and 21.4% respectively (p = 0.047).

CONCLUSION

In general medicine wards, modified prehospital hypoglycaemic regimens and a basal/bolus insulin regimen achieve similar glucose control. The clinical outcome was not affected by the modality of glucose control.

Increased ERK and JNK activities correlate with disease activity in patients with systemic lupus erythematosus

BACKGROUND

Aberrant signalling along the p21ras/MAP kinase pathway has been demonstrated in systemic lupus erythematosus (SLE).

OBJECTIVE

To determine whether expression and activity of the MAP kinases ERK and JNK reflect disease activity in patients with SLE.

METHODS

Blood samples of 42 outpatients with SLE were prospectively collected during four consecutive visits. The control group included 20 healthy subjects. Disease activity was assessed using the SLE Disease Activity Index (SLEDAI). Expression of total ERK and JNK kinases and their active forms (pERK and pJNK) was determined in whole protein lysates of peripheral blood mononuclear cells.

RESULTS

The mean levels of the active kinases pERK and pJNK were significantly increased in patients with active disease (SLEDAI 4-20) as compared with patients with inactive disease (SLEDAI 0-3), p = 0.04, as well as with healthy controls, p = 0.03 and p = 0.003 for pERK and pJNK, respectively. The percentage of activated forms of ERK and JNK of the total expression of these MAP kinases was also gradually increased, reaching 50% for pERK and >40% for pJNK in patients with SLE with moderate-to-severe disease (SLEDAI 7-20), p = 0.005, p = 0.005 and p = 0.02, p = 0.05 as compared with controls and inactive patients, respectively. A decrease of more than three SLEDAI points was associated with a significant reduction in the expression of both total and activated forms of ERK and JNK, p = 0.03, p = 0.01, respectively.

CONCLUSIONS

The results show that ERK and JNK activity reflects disease activity in patients with SLE. These MAP kinases may serve as additional tools for the evaluation of disease activity and management of these patients.

Evidence for aberrant regulation of MAP kinase signal transduction pathway in peripheral blood mononuclear cells in patients with active celiac disease

BACKGROUND

Aberrant signaling via the p21/mitogen-activated proteins (MAP) kinase pathway has been described in lymphocytes of patients with various autoimmune diseases. There is little published data about the intracellular mediators and signals that regulate expression and activity of transcription factors and their effect on celiac disease induction and progression.

AIM

To investigate the possible involvement of MAP kinase pathway in peripheral blood mononuclear cells (PBMC) in celiac disease and its correlation with disease activity.

METHODS

Expression of the total and activated forms of two MAP kinases [extracellular response kinase (ERK) and c-Jun amino terminal kinase (JNK)] were studied by Western blots in PBMC of 17 untreated and 19 treated celiac patients, and 17 controls. Seven of these untreated celiac patients were studies before and after 6 months of gluten-free diet.

RESULTS

Phosphorylated ERK of active celiac disease patients was significantly lower compared with controls (P < 0.01) and was increased towards normal after 6 month of gluten-free diet (P < 0.01). Phosphorylated JNK was increased significantly in the untreated celiac group (P < 0.01) and normalized towards the control level after 6 months of gluten-free diet (P < 0.04).

CONCLUSIONS

Aberrant MAP-kinase pathway activity is associated with active celiac disease (CD). Further studies should examine the potential role of this aberration in pathogenesis of CD.

An open-label study of citalopram for major depression following traumatic brain injury

Major depression is associated with substantial psychosocial dysfunction and post-concussive symptomatology following traumatic brain injury (TBI). Studies to date of anti-depressant treatment for major depression post-TBI have been limited by small sample size. The goal of the present study is to examine the rates of response and remission associated with citalopram treatment for major depression following traumatic brain injury. Subjects with major depression following mild-to moderate TBI were treated with open-label citalopram with a starting dose of 20 mg/day to a maximum of 50 mg/day for either 6 weeks (n = 54) or 10 weeks (n = 26). The Hamilton Depression Rating Scale (HAMD) was used to assess depression severity. Response was defined by a 50% reduction in HAMD score, and remission was defined by a HAMD score of < or =7. The mean HAMD at baseline and 6 weeks were 23.66 (SD 6.8) and 16.30 (SD 9.3), respectively (t[53] = 7.157, p < 0.0001). The mean HAMD at 10 weeks was 12.96 (SD 7.9) (t[25] = 7.323, p < 0.0001). At 6 weeks, 54 subjects were assessed and 27.7% responded with 24.1% in remission. At 10 weeks, 26 subjects were assessed and 46.2% responded with 26.9% in remission. The response rate in the present sample was substantially lower than previously reported for patients with TBI, but comparable to the results of the largest effectiveness trial of citalopram for general out-patients with major depression in the absence of TBI.

Acute psychotic stress is associated with decreased adiponectin serum levels

OBJECTIVE

To determine the effect of acute psychotic stress on adipokine secretion in non-diabetic subjects.

RESEARCH DESIGN AND METHODS

Adiponectin, leptin, and cortisol serum levels were determined in 39 non-diabetic patients with acute psychotic stress reaction admitted to a psychiatric ward. The clinical global impression (CGI) score was used to evaluate the level of psychotic stress. Insulin sensitivity (IS) was determined by the homeostasis model assessment (HOMA). Patients were re-assessed 2 weeks after admission. During hospitalization patients were treated for variable times with either phenothiazines or thioxanthenes.

RESULTS

The mean CGI score decreased significantly with time: 5.3+/-0.8 and 2.6+/-0.8 on admission and after 2 weeks respectively (p<0.001). On admission, the mean adiponectin level was significantly lower in patients compared to normal controls: 15.3+/-8.2 mug/ml and 26+/-12.8 mug/ml, respectively (p=0.02). It increased significantly after 2 weeks to 18.2+/-10 mug/ml (p=0.003). By contrast, the leptin and cortisol levels did not change significantly. No correlation was found between the changes in individual CGI scores and adiponectin levels. However, female patients with the highest stress on admission demonstrated the lowest adiponectin levels and insulin sensitivity: p=0.002 and 0.03 respectively.

CONCLUSIONS

These data suggest a link between acute psychotic stress reaction and decreased serum adiponectin levels. Further studies are recommended to determine the strength of this association.

Reduction of digital plantar pressure by debridement and silicone orthosis

The lesser digits are frequent sites of elevated plantar pressure and ulceration in the diabetic foot. We sought to determine whether debridement of callus and the wearing of a custom molded digital orthosis could significantly reduce digital plantar pressure. Fourteen patients with distal digital callus were studied. For each patient, the toe with the highest plantar pressure was selected. A computerized pressure mat was used to record the plantar pressure before and after debridement with and without a moldable silicone digital orthosis. Mean peak plantar digital pressures before treatment were 2.80+/-0.7 kg/cm2 for the entire group. The digital orthosis alone reduced plantar pressure to a mean of 1.95+/-0.65 kg/cm2 p < 0.05. Treatment by debridement similarly reduced pressure to 1.99+/-0.76 kg/cm2 p < 0.05. The most effective reduction of pressure for all patients, as well as the most statistically significant, occurred when both treatments were given, with mean peak plantar pressure falling to 1.28+/-0.61 kg/cm2 p < 0.01. Debridement and custom molded digital orthoses alleviate distal digital plantar pressure. Since elevated plantar pressure increases the risk of neuropathic ulceration, these treatments should be considered in the prophylactic care of appropriate patients.

Successful treatment of prolonged agranulocytosis caused by acute parvovirus B19 infection with intravenous immunoglobulins

A 21-year-old previously healthy male presented with prolonged fever of 3 weeks duration and profound agranulocytosis that did not respond to treatment with granulocyte-stimulating factors. A bone marrow biopsy demonstrated an absence of myeloid lineage. Acute parvovirus B19 infection was diagnosed by the presence of both IgM and IgG anti-parvovirus antibodies. Two days treatment with intravenous immunoglobulins (IVIg) resulted in complete recovery. The role of treatment with immunoglobulins in acute and persistent parvovirus infection is discussed.

Clinical characteristics and diabetes associated autoantibodies in patients with both type 1 diabetes mellitus and asthma

OBJECTIVE

Type 1 diabetes mellitus (DM1) and asthma are mediated by opposite arms of the cellular immune system, namely T helper (Th)1 and Th2 CD4+ cells, respectively. It is not known whether their coexistence affects their clinical manifestations.

METHODS

The number of asthma exacerbations, frequency of hypoglycemic events, HbA1c levels, diabetes associated autoantibody status and diabetes associated late complications were determined in three paired groups of patients (n = 11) matched by gender and age: DM1 and asthma, asthma only, and DM1 only.

RESULTS

Patients with both diseases had a higher prevalence of hypoglycemic events per month compared to patients with DM1 only: 5.67 +/- 4.27 vs 1.45 +/- 2.06, respectively (p = 0.008). The co-existence of the two diseases did not modify the remaining clinical and laboratory parameters.

CONCLUSION

Patients with both DM1 and asthma have similar clinical characteristics to patients with only one of these diseases apart from a higher rate of hypoglycemic events compared to patients with DM1 without asthma.

Increased expression of tissue factor and receptor for advanced glycation end products in peripheral blood mononuclear cells of patients with type 2 diabetes mellitus with vascular complications

The aim of the study was to determine the correlation between the expression of tissue factor (TF) and the receptor for advanced glycation end products (RAGEs) and vascular complications in patients with longstanding uncontrolled type 2 diabetes (T2D). TF and RAGE mRNAs as well as TF antigen and activity were investigated in 21 T2D patients with and without vascular complications. mRNA expression was assessed by reverse transcriptase–polymerase chain reaction (RT-PCR) in nonstimulated and advanced glycation end product (AGE) albumin–stimulated peripheral blood mononuclear cells (PBMCs). TF antigen expression was determined by enzyme-linked immunosorbent assay (ELISA) and TF activity by a modified prothrombin time assay. Basal RAGE mRNA expression was 0.2 ± 0.06 in patients with complications and 0.05 ± 0.06 patients without complications (P = .004). Stimulation did not cause any further increase in either group. TF mRNA was 0.58 ± 0.29 in patients with complications and 0.21 ± 0.18 in patients without complications (P = .003). Stimulation resulted in a nonsignificant increase in both groups. Basal TF activity (U/10⁶ PBMCs) was 18.4 ± 13.2 in patients with complications and 6.96 ± 5.2 in patients without complications (P = .003). It increased 3-fold in both groups after stimulation (P = .001). TF antigen (pg/10⁶ PBMCs) was 33.7 ± 28.6 in patients with complications, 10.4 ± 7.8 in patients without complications (P = .02). Stimulation tripled TF antigen in both groups of patients (P = .001). The RAGE/TF axis is up-regulated inT2Dpatients with vascular complications as compared to patients without complications. This suggests a role for this axis in the pathogenesis of vascular complications in T2D.

Swab cultures accurately identify bacterial pathogens in diabetic foot wounds not involving bone

AIMS

Current clinical practice assumes swab cultures from wounds are unreliable. However, this assumption is based upon data culled only from wounds in which osteomyelitis and/or gangrene were present. This study aimed to re-evaluate the accuracy of swab cultures vs. deep tissue cultures in diabetic wounds of varying depth and severity.

METHODS

A total of 60 infected diabetic foot wounds were cultured. Two specimens were taken from each wound: superficial swab before debridement and deep tissue specimen towards the end of surgical debridement.

RESULTS

In 37 wounds (62%), the micro-organisms isolated from the swab specimen and those isolated from the deep tissue specimen were identical. In another 12 wounds (20%), the swab culture contained all micro-organisms isolated from the deep tissue culture, but also contained additional micro-organisms. Analysis according to the depth of the wound, demonstrated that swabs identified all micro-organisms isolated from the deep tissue specimens in 36/40 wounds (90%) that did not extend to bone as opposed to 13/20 wounds (65%) that extended to bone.

CONCLUSIONS

Swab cultures are valuable in identifying pathogens in diabetic foot wounds when bone is not involved. When surgical debridement is contraindicated or delayed, swab cultures can be used to select appropriate antibiotic therapy.

Enhanced glucose-dependent glucagon-like peptide-1 and insulin secretion in Crohn patients with terminal ileum disease is unrelated to disease activity or ileal resection

BACKGROUND

Enhanced secretion of glucagon-like peptide-1 (GLP-1) has been reported in patients with Crohn disease (CD). However, the correlation between the enteropancreatic axis and the activity of CD remains unclear.

METHODS

Plasma glucose, insulin, GLP-1 levels and insulin sensitivity were determined before and after oral glucose tolerance tests in 13 patients with CD of the terminal ileum, in 13 patients after resection of the terminal ileum and in 7 healthy controls. Basal and stimulated insulin sensitivities were determined using the homeostasis model assessment (HOMA) and the insulin sensitivity index (ISI) methods, respectively.

RESULTS

Basal and stimulated glucose levels were comparable in patients and controls. The peak stimulated GLP-1 secretion was significantly higher in the patient group compared to controls: 12.2 +/- 1.24 pM/L and 8.1 +/- 1.72 pM/L, respectively, P=0.03. This was associated with 52% increased overall insulin secretion in the patients' group as compared to controls (P=0.007) and a higher peak insulin response: 63.5 +/- 9.69 mU/L and 41.5 +/- 6.85 mU/L for patients and controls, respectively, P=0.04. Operated patients had similar GLP-1 levels but higher peak and overall insulin secretions compared with those in non-operated patients (P=0.01). Fasting and stimulated insulin sensitivities were reduced only in patients with ileal resection as compared to controls: P=0.01 and P=0.05, respectively. No correlation was found between the CD activity index and GLP-1 or insulin secretion.

CONCLUSIONS

CD of the terminal ileum is associated with enhanced glucose-dependent GLP-1 secretion, which is unrelated to disease activity or ileal resection.

Normal p21Ras/MAP kinase pathway expression and function in PBMC from patients with polycystic ovary disease

Polycystic ovary disease (PCOD) is associated with insulin resistance and increased prevalence of type II diabetes mellitus (T2DM). The p21Ras/MAP kinase is a major intracellular signaling pathway mediating insulin signaling in insulin responsive tissues. The expression, regulation and function of the p21Ras/MAP kinase pathway in PCOD patients were examined. Peripheral blood mononuclear cells (PBMC) were isolated from ten patients with PCOD and ten controls. The expression of p21Ras and its regulatory proteins; hSOS1 and p120GAP were studied. The basal and phytohemaglutinin (PHA) or insulin stimulated phosphorylation of MAP kinase was determined. Expression of p21Ras, and its regulatory proteins hSOS1 and p120GAP were similar in PCOD patients and controls. Basal, PHA and insulin stimulated phosphorylation of MAP kinase, were also comparable in the two groups as well as their PBMC proliferative response. These data indicate that the expression and overall function of the p21Ras/MAP kinase pathway remain intact in non-diabetic patients with PCOD.

Diagnosis of normocalcemic hyperparathyroidism by oral calcium loading test

We evaluated the oral calcium-loading test (OCLT) in diagnosing normocalcemic primary hyperparathyroidism. Calcium and PTH levels were measured before, 60, 120 and 180 min after oral 1 g of calcium gluconolactate administration in 102 consecutive females with high circulating PTH levels, and 25 controls. Patients were classified as follows: Group A, patients with a parathyroid adenoma identified by two imaging modalities. Sub-Group AO, hyperparathyroid patients [no.=13, mean age 59 yr (SD=10)] evaluated prior to parathyroidectomy. Sub-Group AH, non-operated hypercalcemic patients [no.=29, age 63 yr (SD=11)]. Sub-Group AN, normocalcemic non-operated women [no.=14, age 59 yr (SD=8)]. Group B, normocalcemic individuals [no.=46, age 58 yr (SD=11)] with negative parathyroid imaging. Group C, control patients [no.= 25, age 56 yr (SD=12)]. The concentrations of calcium and PTH overlapped in the normocalcemic groups during the OCLT. Product P, defined as circulating PTH nadir (pg/ml) x peak calcium concentration (mg/dl), better discriminated Sub-Group AN from Group B, AUC=0.98 (95% CI 0.95, 1.00) than did Ratio R, defined as relative PTH decline/relative calcium increment, AUC= 0.86 (95%CI 0.73, 0.99). Assuming normal threshold of Product P and Ratio R at 260 and 17 respectively, the combined parameters diagnose normocalcemic hyperparathyroid patients with 100% sensitivity and 87% specificity.

Lack of correlation between disease activity and decreased stimulated secretion of IL-10 in lymphocytes from patients with celiac disease

BACKGROUND

Celiac disease (CD) is commonly believed to be a predominantly Th1 disease. However, the exact balance between the Th1 and Th2 arms, as well as the correlation to clinical parameters, remains unclear. The aim was to assess the Th1/Th2 cytokine profile and its correlation to clinical parameters in active and non-active CD patients.

METHODS

Peak, total secretion and secretory pattern of the Th1 cytokines (IFN-gamma and IL-2) and Th2 cytokines (IL-4 and IL-10) were determined in resting and stimulated peripheral blood mononuclear cells (PBMC) from 19 CD patients with active and non-active disease and 20 normal controls.

RESULTS

Peak and total secretion of IL-10 were significantly reduced in CD patients compared with normal controls. This was due to a persistently flat secretory pattern of IL-10 over time in CD patients. In addition, IFN-gamma/IL-10 and the IL-2/IL-10 ratios of peak and total secretion were higher in patients than in controls. In contrast, peak, total secretion and secretory pattern of IL-2, IFN-gamma and IL-4 were comparable in patients and controls as well as the IL-2/IL-4 and IFN-gamma/IL-4 ratios. No difference in the cytokine secretion or Th1/Th2 ratio was found between active and non-active patients or between pediatric and adult patients.

CONCLUSIONS

These data indicate that the Thl/Th2 balance in CD is shifted towards Th1 cytokines because of a down-regulated IL-10 secretion. The aberrant profile of cytokine secretion of these patients is not associated with clinical parameters and suggests an inherent defect in IL-10 secretion in CD.

The relation between adrenal function and the severity of bronchial hyperresponsiveness in children as measured by the methacholine provocation test

BACKGROUND

There is no satisfactory explanation why some individuals experience severe attacks of asthma, yet others, exposed to similar stimuli, have a milder form of the disease.

OBJECTIVE

We tested the hypothesis that children with more severe disease may have relative adrenal insufficiency compared to the children with milder disease.

PATIENTS AND METHODS

Sixteen children with chronic asthma aged 8-16 years old were studied. Adrenal function was evaluated by the 24-h excretion of urinary free cortisol (UFC) before and after ACTH stimulation, and by plasma cortisol levels before and 60 min after ACTH administration. The severity of bronchial hyperresponsiveness was evaluated by the methacholine provocation test.

RESULTS

Nine children had 20% fall in forced expiratory volume in 1 sec (FEV1) after a provocative concentration (PC20FEV1) of methacholine > or =2.5 mg/ml and were considered as having mild-moderate bronchial hyperresponsiveness (Group A). Seven children had a PC20FEV1 of < or =1.25 mg/ml and were considered as having severe bronchial hyperresponsiveness (Group B). No significant difference was found between the peak plasma cortisol response to ACTH between the two groups (634+/-182 and 586+/-137 nmol/l, respectively). However, there was a significant statistical difference (p <0.01) in the 24-h UFC response to ACTH between the children from Group A (345+/-107 nmol/m2 ) and the children from Group B (161+/-125 nmol/m2).

CONCLUSIONS

Based on the low levels of 24-h UFC secretion in severely asthmatic children in our study, we propose the encouragement of provision of a short course of inhaled steroids to be kept at home for the emergency therapy of those children identified as having high-risk asthma.

Age and functioning after mild traumatic brain injury: the acute picture

HYPOTHESIS

There will be acute harbingers of poor outcome following mild traumatic brain injury (TBI) in the elderly.

PARTICIPANTS

Twenty-six subjects age 60 and over were compared to 30 subjects aged 18-59, seen within 1 month, on average, following a mild TBI.

MAIN OUTCOME MEASURES

Functioning was assessed using the Glasgow Outcome Scale (GOS), a global measure of outcome, as well as self-report measures of psychosocial functioning, physical symptoms and psychological distress.

RESULTS

Contrary to the hypothesis, the older group did better than their younger counterparts on the GOS (p = 0.002), and reported less psychosocial impairment (p < 0.0001), less psychological distress (p = 0.002), and less physical symptoms (p = 0.005). However, once employment was controlled for, these results only approached statistical significance.

DISCUSSION

The assumption that elderly subjects have a worse outcome following TBI needs to be reconsidered, at least within the acute recovery period. The importance of psychosocial factors as modifiers of outcome according to age are emphasized. Whether this finding holds true over a longer follow-up period is the subject of ongoing research.

The effect of Losartan on insulin resistance and beta cell function in chronic hemodialysis patients

Insulin resistance (IR) is prevalent in hemodialysis patients. IR and hyperinsulinemia have an important role in the development of atherosclerosis, which is the most common cause of morbidity and mortality in hemodialysis patients. Thus, antihypertensive drugs that lower IR, may have an additional beneficial effect in the treatment of cardiovascular diseases in these patients. In this preliminary study we examined the effect of Losartan (an angiotensin II receptor antagonist) treatment on IR and beta cell function in five hypertensive non-diabetic chronic hemodialysis patients. All other known causes of IR in end stage renal failure were excluded. After a washout period of two weeks, Losartan 50 mg, was administered for 6 weeks. Fasting blood glucose (FBG) and insulin levels were measured before and after the treatment IR and beta cell function were calculated using the "homeostasis model assessment"-HOMA. Systolic and diastolic blood pressure (BP) have not changed significantly throughout the study. FBG increased significantly from 76 mg/dL +/- 1 to 89 mg/dL +/- 4 (p < 0.01), however, insulin levels have not changed significantly. Calculated IR values did not show a difference, but calculated beta cell function decreased significantly after Losartan treatment from 291% +/- 50 to 146% +/- 10, (p < 0.016). These preliminary results suggest that in chronic hemodialysis hypertensive non-diabetic patients short treatment with Losartan has deleterious effect on glucose homeostasis mediated via a decrease in beta cell function.

The immunomodulator Linomide: role in treatment and prevention of autoimmune diabetes mellitus

Insulin-dependent diabetes mellitus (IDDM) is considered to be an autoimmune disorder characterized by destruction of the pancreatic beta-cells by auto-reacting lymphocytes. An attractive therapeutic approach to this disease would be to abrogate the autoimmune process at an early stage, thus preserving a critical mass of pancreatic beta-cells necessary for maintenance of normal glucose tolerance. Linomide (quinoline-3-carboxamide, Roquinimex, LS 2616), is a novel, orally absorbed, immunomodulatory drug that has been shown to be effective in various models of autoimmunity without causing non-specific immunosuppression. In this review, we describe the efficacy of Linomide for ameliorating the autoimmune process and diabetes in the non-obese diabetic (NOD) model of IDDM when administered at early stages of the disease. We also show that advanced disease in the NOD mouse can be treated effectively by combining Linomide with therapeutic modalities designed to increase pancreatic beta-cell mass. Subsequent clinical studies have shown that Linomide preserves beta-cell function in individuals with new-onset IDDM. Based on these data, Linomide or derivatives thereof might be useful for treatment of human IDDM.

Acute inflammatory myopathy with severe subcutaneous edema, a new variant? Report of two cases and review of the literature

Acute inflammatory myopathy with severe subcutaneous edema is extremely rare and has been reported in only a handful of cases. We describe two similar patients presenting with this disorder and generalized rash. Unlike the five previously reported cases, the clinical and histologic features of our two patients are more suggestive of dermatomyositis than polymyositis. Nevertheless, scrutinizing all seven reported patients, a number of specific characteristics could be defined. All patients were adult males. Dysphagia was present in four. In six patients, acute inflammatory myopathy was idiopathic while malignancy was present in one. Two patients died despite intensive therapy, three improved on corticosteroid treatment, and two recovered spontaneously. In all patients, limb involvement with marked subcutaneous edema was present, clinically mimicking deep vein thrombosis in both our patients. The presence of severe subcutaneous edema may be a hallmark of a distinctive variant of acute inflammatory myopathy. More cases are needed to discern subtypes of this general entity and to establish guidelines for treatment and prognosis.

Relationship of psychosis to aggression, apathy and function in dementia

BACKGROUND

Psychosis has been associated with aggression in dementia, but the nature of this relationship has been unclear. There has been very little research into the relations between apathy and functional status to psychosis in dementia. The purpose of this study is to investigate the relationship between psychosis and aggression, apathy, and functional status in outpatients with dementia.

METHODS

The presence of psychosis was assessed by clinical interview and two scales: the Neuropsychiatric Inventory and the Columbia University Scale for Psychopathology in Alzheimer's Disease. The maximum likelihood estimation technique was used to determine the best estimate of the presence of psychosis. Aggression, apathy, and functional status (activities of daily living: ADLs) were measured using structured instruments.

RESULTS

Sixty-one subjects were included. The CUSPAD and NPI provided low false positive and negative rates. ANCOVA analyses showed that psychosis was significantly associated with aggression, even when controlling for apathy, depression, and ADLs. Psychosis was related to apathy only when depression was controlled for. Hallucinations were related to impaired basic ADLs, even when depression and apathy were controlled for.

CONCLUSIONS

Relationships were found between psychotic symptoms in dementia and aggression as well as apathy and impaired functional status. These relationships suggest pathophysiologic mechanisms and have possible treatment implications.

High insulin requirements and poor metabolic control do not modify the expression, regulation and PKC mediated activation of the p21ras pathway in PBMC from type II diabetic patients

AIMS

To asses whether clinically severe insulin resistance and poor metabolic control in patients with type 11 diabetes are associated with aberrant expression or function of the p21ras pathway.

METHODS

We examined the expression and function of the p21ras pathway in resting and activated PBMC from 10 insulin treated patients with type II diabetes characterized by high insulin requirements and poor metabolic control (IR group) and 10 age and sex matched well controlled patients treated by diet alone or oral hypoglycemic medications (WC group).

RESULTS

Levels of p21ras and its regulatory elements: p21rasGAP and hSOS1, were comparable in the two groups. The induced activities of p21ras and its associated down-stream regulatory enzyme MAP-kinase following TPA stimulation were also comparable in the IR and WC patients.

CONCLUSIONS

Taken together, these data indicate that clinically significant severe insulin resistance does not modify the expression, regulation and activation of p21ras pathway in PBMC of patients with type II diabetes.

T cell signaling and autoimmune diabetes

Stimulation of the T-cell lymphocyte surface receptor (TCR) initiates a cascade of intracellular signaling events leading to proliferation, anergy, cytokine secretion, or apoptosis. In prediabetic NOD mice, T cell proliferative hyporesponsiveness has been correlated to decreased TCR-mediated signal transduction along the PKC/p21ras/p42mapk pathway. Limited data regarding T cell signaling defects are available in patients with autoimmune diabetes mellitus. Some but not all investigators have found decreased in vitro proliferative hyporesponsiveness to lectin mitogens or anti-CD3 mAb associated with impaired PKC activation and cytokine production. More recently, defective expression and function of the p21ras cascade was reported in these patients. Taken together, these data suggest that lymphocytes from animals and patients with autoimmune diabetes have defective TCR mediated signaling which may result in aberrant T cell activation and proliferation. This may lead to an imbalance of Th1/Th2 cytokine secretory pattern and thereby promote disease development.

Inactive systemic lupus erythematosus id associated with a normal stimulated Th(1)/Th(2) cytokine secretory pattern

OBJECTIVES

To determine the Th(1)/Th(2)balance in systemic lupus erythematosus (SLE) patients with inactive disease.

METHODS

A comprehensive analysis of peak secretion, overall cytokine production and secretory pattern of Th(1)and Th(2)cytokines from stimulated PBMC of 10 SLE patients with inactive disease and 10 age- and sex-matched controls.

RESULTS

No significant differences were found in the peak and total secretion of all cytokines, as well as in the Th(1)and Th(2)secretory patterns and proliferative response between the two groups.

CONCLUSION

Th(1)and Th(2) balance in inactive SLE is normal.

Outcome following traumatic brain injury in the elderly: a critical review

BACKGROUND

The elderly are at risk for traumatic brain injury (TBI), but their outcome following these injuries remains unclear.

OBJECTIVE

This paper critically reviews research done to date on cognitive and functional outcome following TBI in the elderly.

METHODS

MEDLINE and PSYCHLIT databases going back to 1965 were searched.

RESULTS

Studies suggest that TBI results in adverse cognitive and functional outcomes in the elderly. There is uncertainty as to whether TBI is a significant risk factor for Alzheimer's disease (AD). Methodological problems in these studies include selection bias, small samples, retrospective analyses, and, particularly, the failure to address the role of pre-morbid functioning. These problems limit the strength of the outcome studies, and may account for the equivocal findings on AD risk.

CONCLUSIONS

It is premature to conclude from the published research to date that the elderly have a uniformly poor outcome following TBI. Directions for further research are suggested.

[Epstein-Barr virus infections in adults: a diagnostic challenge]

The adult form of mononucleosis caused by Ebstein-Barr virus (EBV) is different from the disease in children and adolescents. In most adults there is no pharyngitis or lymphadenopathy, fever is much more prolonged, abnormal liver function is frequent and lymphocytosis and the presence of atypical lymphocytes are not common. Such an atypical disease presentation often results in delayed diagnosis and unnecessary treatments. We describe 2 adults with such atypical presentations and complications of EBV infection.

IL-17 regulates gene expression and protein synthesis of the complement system, C3 and factor B, in skin fibroblasts

Human IL-17 is a cytokine secreted by CD4+-activated memory T cells with the profile of effects of a Th1 cytokine. The effects of IL-17 on many cellular constituents of joints suggest that it may participate in inflammatory joint diseases. Proteins of the complement system are known to be regulated by pro- and anti-inflammatory cytokines. The purpose of this work was to study the effect of IL-17 alone and combined with tumour necrosis factor (TNF) on the expression and synthesis of factor B and C3. Fibroblasts were stimulated with the relevant cytokine or cytokines, pulse labelled with 35S-methionine, and the newly synthesized proteins were immunoprecipitated and subjected to SDS-PAGE. Gene expression was determined by Northern blot analysis. IL-17 10 ng/ml induced increases in gene expression and protein synthesis of C3, 2.25 +/- 0.26- and 2.7 +/- 0.7-fold, respectively with concomitant non-significant effects on factor B, 1.5 +/- 0.45- and 2.2 +/- 1. 2-fold, respectively. When both IL-17 and TNF were present simultaneously, the synthesis of factor B increased by 85% more than the expected additive effects of these cytokines separately, while for C3 the effect of both cytokines was 19% lower than the expected additive effect (observed/expected = 0.81). IL-4 reduced the synergistic effect by 50%. We conclude that IL-17 has a regulatory role on C3 expression and synthesis and an amplifying effect on TNF-induced factor B synthesis. Taken together with the evidence that TNF is a major cytokine involved in the inflammation of rheumatoid arthritis, it suggests that IL-17 has a proinflammatory role in the inflammation process of joints. The distinct effects of IL-4, IL-17 and TNF on the synthesis of factor B in fibroblasts suggest that factor B and the alternative pathway of the complement system may play an important role in joint inflammation.

Defective activation of p21ras in peripheral blood mononuclear cells from patients with insulin dependent diabetes mellitus

We previously reported that a decreased TCR mediated activity of the GTP-GDP binding p21ras protooncogene is associated with prediabetes in non-obese diabetic (NOD) mice. Furthermore, prevention of autoimmune diabetes is associated with reversal of the p21ras signaling defect in NOD T cells. Based on these animal studies we determined the activation of p21ras in PBMC from patients with Insulin Dependent Diabetes Mellitus (IDDM), Non-Insulin Dependent Diabetes Mellitus (NIDDM) and normal healthy controls. Stimulation by PHA induced a decrease of 3.7 +/- 1.4% and an increase of 2.44 +/- 2.3%, p < 0.02 and 2.6 +/- 1.6%,p < 0.003 in the basal unstimulated p21ras activity in the IDDM, NIDDM and normal control groups, respectively. Expression of p21ras and its regulatory elements, the GTPase activating protein p120ras-GAP and the guanine nucleotide releasing factor (GNRF) hSOS, was comparable in the three groups. The in vitro proliferative response to PHA was comparable in the IDDM and control groups: stimulation index (SI) of 8.6 +/- 2.5 and 9.4 +/- 3.5 respectively, p < 0.44. No correlations were found in the IDDM patients between the degree of p21ras activation and the mitogen induced in vitro proliferative response or the various clinical parameters including age, gender, disease duration, daily insulin requirements and metabolic control. Taken together these data indicate that PBMC from IDDM patients are characterized by a persistent impairment in the activation of their p21ras. They also suggest that p21ras stimulated activity is a sensitive and independent parameter of PBMC activation in these patients.

Decreased expression of the p21ras stimulatory factor hSOS in PBMC from inactive SLE patients

Expression of the p21 ras protooncogene is reported to be increased in animal models and in patients with SLE. However, the expression of p21ras regulatory elements has not been determined. We determined the expression of p21ras, and its regulatory elements p120-ras-GAP and hSOS, in PBMC of 10 patients with inactive SLE (mean SLEDAI score 1.8+/-0.53) and 10 age- and sex-matched healthy controls. No difference was found between the two groups in the levels of p21 ras (3760+/-513 and 3367+/-335, P=0.25) and ras-GAP (1048+/-261 and 1534+/-247, P=0.11) in patients and controls, respectively. In contrast, levels of hSOS were significantly decreased in patients as compared to controls: 955+/-218 and 2306+/-327, P = 0.002, respectively. The mitogen-induced proliferative response was comparable in the two groups: SI 20.8+/-4.2 and 15.03+/-4.9, P=0.135, in patients and controls, respectively. Taken together, our data demonstrate that nonactive SLE patients are characterized by reduced hSOS expression and underscore the need for a comprehensive evaluation of p21ras pathway in these patients.

Decreased secretion of Th2 cytokines precedes Up-regulated and delayed secretion of Th1 cytokines in activated peripheral blood mononuclear cells from patients with insulin-dependent diabetes mellitus

Recent evidence suggests that autoimmune animal diabetes is associated with an imbalance between the Th1 and Th2 arms of the cellular immune system. However, limited data is available regarding the Th1/Th2 imbalance in human Insulin dependent diabetes mellitus (IDDM) patients. Therefore, we examined the peak levels, secretory pattern and total cytokine production (calculated as the area under the curve, AUC) of the Th1 cytokines, IL-2 and IFN-gamma, and Th2 cytokines, IL-4 and IL-10, from stimulated peripheral blood mononuclear cells, from 17 IDDM patients and 24 normal controls. In contrast to controls, diabetic patients were characterized by an early, uniformly low secretion of Th2 cytokines, followed by a late increased secretion of Th1 cytokines. This resulted in significant differences in secretory patterns of IFN-gammaIL-2, IL-4 and IL-10 between the two groups; P<0.001, P<0.005, P<0.005 and P<0.001, respectively. No correlation was found in the diabetic patients between any profiles of the cytokines and their various clinical parameters, including age, gender, disease duration, insulin requirements or glycated hemoglobin levels. In conclusion, our data provides the first comprehensive evidence for an independent and persistent impairment of both Th1 and Th2 cytokine secretory patterns in IDDM patients.

Neonatal activation of CD28 signaling overcomes T cell anergy and prevents autoimmune diabetes by an IL-4-dependent mechanism

Optimal T cell responsiveness requires signaling through the T cell receptor (TCR) and CD28 costimulatory receptors. Previously, we showed that T cells from autoimmune nonobese diabetic (NOD) mice display proliferative hyporesponsiveness to TCR stimulation, which may be causal to the development of insulin-dependent diabetes mellitus (IDDM). Here, we demonstrate that anti-CD28 mAb stimulation restores complete NOD T cell proliferative responsiveness by augmentation of IL-4 production. Whereas neonatal treatment of NOD mice with anti-CD28 beginning at 2 wk of age inhibits destructive insulitis and protects against IDDM by enhancement of IL-4 production by islet-infiltrating T cells, administration of anti-CD28 beginning at 5-6 wk of age does not prevent IDDM. Simultaneous anti-IL-4 treatment abrogates the preventative effect of anti-CD28 treatment. Thus, neonatal CD28 costimulation during 2-4 wk of age is required to prevent IDDM, and is mediated by the generation of a Th2 cell-enriched nondestructive environment in the pancreatic islets of treated NOD mice. Our data support the hypothesis that a CD28 signal is requisite for activation of IL-4-producing cells and protection from IDDM.

A study of the clinical differences between women and men with hyperprolactinemia

A group of 64 women and 14 men with hyperprolactinemia were followed up in an endocrine service center for a mean of 43 months. The various parameters in each sex were compared. The mean age at first visit was 49 years in the men and 36 years in the women (p < 0.001). The peak prolactin index levels were 13.7 in the men and 5.5 in the women (p < 0.002). Macroprolactinomas were significantly more prevalent in the men (p < 0.002). The women complained significantly more about headache (p < 0.02), malaise (p < 0.02), restlessness (p < 0.03) and fatigue (p < 0.04). These symptoms had no correlation with the prolactin level. Thus, in the men the clinical manifestations of hyperprolactinemia came to attention at an older age and had a connection with a higher prevalence of macroprolactinoma. The possible mechanisms are discussed. Vague complaints, reported more often by the women, do not seem to correlate with the prolactin level.

Increased prevalence of diabetes-related autoantibodies in celiac disease

Forty-four nondiabetic patients with celiac disease (CD) were examined for the presence of insulin-dependent diabetes mellitus (IDDM)-related autoantibodies. Islet cell antibodies (ICA) were detected in 2 of 44 (4.5%). None of the 200 age- and sex-matched healthy controls was ICA positive (p < 0.05). Competitive anti-insulin antibodies (CIAA) were detected in 1 of 44 (2.5%) patients. First-phase insulin reserve (FPIR), stimulated insulin reserve (SIR), and glycosylated hemoglobin (GHB) levels were normal in the autoantibody-positive patients. Our data suggest that, like first-degree relatives of IDDM patients, CD patients are characterized by an increased prevalence of diabetes-related autoantibodies. Further follow-up is needed to determine whether the presence of these autoantibodies in nondiabetic CD patients predicts future IDDM.

Prevention of autoimmune diabetes by linomide in nonobese diabetic (NOD) mice is associated with up-regulation of the TCR-mediated activation of p21(ras)

Oral therapy with linomide protects prediabetic nonobese diabetic (NOD) mice from insulin-dependent diabetes mellitus. The mechanisms by which linomide exerts its protective effect are not fully understood. A decreased TCR-mediated activity of the GTP-GDP binding p21(ras) proto-oncogene is associated with prediabetes in NOD mice. However, the role of this signal transduction defect in the pathogenesis of autoimmune diabetes is not known. The TCR-mediated and protein kinase C-induced activations of p21(ras) were determined in mononuclear cells from lymph nodes of linomide-treated and untreated prediabetic NOD mice. TCR cross-linking by Con A induced an increase of 13 +/- 6.8% and a decrease of 0.8 +/- 1.8% in p21(ras) activity in the linomide-treated group and the untreated controls, respectively. Cell stimulation with PMA resulted in a 15 +/- 2% increase in p21(ras) activity in the linomide-treated mice and a 10 +/- 11.4% decrease in the untreated mice. Protein levels of p21(ras) and its regulatory elements, the GTPase-activating protein and the guanine nucleotide-releasing factor, mSOS, were comparable in both groups. We, therefore, conclude that prevention of autoimmune diabetes by linomide is associated with up-regulation of the p21(ras) T cell signal transduction defect in NOD mice.

Prevention of autoimmune diabetes by linomide in nonobese diabetic (NOD) mice is associated with up-regulation of the TCR-mediated activation of p21(ras)

Oral therapy with linomide protects prediabetic nonobese diabetic (NOD) mice from insulin-dependent diabetes mellitus. The mechanisms by which linomide exerts its protective effect are not fully understood. A decreased TCR-mediated activity of the GTP-GDP binding p21(ras) proto-oncogene is associated with prediabetes in NOD mice. However, the role of this signal transduction defect in the pathogenesis of autoimmune diabetes is not known. The TCR-mediated and protein kinase C-induced activations of p21(ras) were determined in mononuclear cells from lymph nodes of linomide-treated and untreated prediabetic NOD mice. TCR cross-linking by Con A induced an increase of 13 +/- 6.8% and a decrease of 0.8 +/- 1.8% in p21(ras) activity in the linomide-treated group and the untreated controls, respectively. Cell stimulation with PMA resulted in a 15 +/- 2% increase in p21(ras) activity in the linomide-treated mice and a 10 +/- 11.4% decrease in the untreated mice. Protein levels of p21(ras) and its regulatory elements, the GTPase-activating protein and the guanine nucleotide-releasing factor, mSOS, were comparable in both groups. We, therefore, conclude that prevention of autoimmune diabetes by linomide is associated with up-regulation of the p21(ras) T cell signal transduction defect in NOD mice.

Routine childhood screening for hyperlipidemia in Israel

Screening of children and adolescents for hyperlipidemia is controversial. We performed a cholesterol surveillance study of 806 children aged between 6 and 14 years. The initial cholesterol screening test was done by finger stick in the non-fasting state. Children with cholesterol values exceeding 4.55 mmol/l ("borderline" risk) and their parents had their lipid profiles measured following a 12 h fast by venipuncture. The incidence of coronary risk factors in the families of children with hypercholesterolemia was estimated. Of the initial group, 71 children had total capillary cholesterol levels > or = 4.55 mmol/l, and in 65 of these children serum lipid profile was reexamined after an overnight fast. Fifty-five children were found to have total venous cholesterol (TVC) levels < 4.55 mmol/l, and 27 of the 55 had a low density lipoprotein (LDL) cholesterol level > 3.4 mmol/l ("borderline" risk). A positive correlation was found between TVC and LDL-cholesterol levels. Of the hypercholesterolemic children 49% had a parent with hyperlipidemia and 13% had a family history of premature myocardial infarction (before 55 years of age). We conclude that screening of children based on the presence of hypercholesterolemia or its possible complications in other family members may fail to identify many of the children with hypercholesterolemia. Thus, if thorough identification of young children with hypercholesterolemia is desired, inclusive population screening would be the most effective approach.

Lactogenic hormones rapidly activate p21( ras )/mitogen-activated protein kinase in Nb2-11C rat lymphoma cells

Lactogenic hormone-dependent Nb2-11C cells proliferate in response to prolactin (PRL) or human growth hormone (hGH). We have investigated the activation of p21( ras ) and mitogen-activated protein kinase (MAP-kinase) by hGH in lactogen-dependent Nb2-11C and in autonomous hormone-independent Nb2-SP rat lymphoma cells. Exposure of Nb2-11C cells to hGH resulted in a dose-dependent activation of p21( ras ) and of MAP-kinase. Activation occurs at physiological hGH concentration and with a rapid onset (∼1 min) reaching maximal level at 10-20 min. In contrast, in Nb2-SP autonomous lactogen-independent cells, p21( ras ) and MAP-kinase are constitutively activated and a challenge with lactogenic hormone had a modest additional activating effect. TPA, an activator of protein kinase C, enhanced p21( ras ) and MAP-kinase activity in Nb2-11C cells but failed to induce proliferation. The mechanism of activation of p21( ras ) in Nb2-11C cells by lactogenic hormones involves both an increased binding of guanine nucleotides to p21( ras ) as well as an increase in GTP/GDP+GTP ratio. In summary, we have demonstrated here that activation of the p21( ras )/MAP-kinase pathway follows PRL receptor activation but is not sufficient for the lactogenic hormone-dependent mitogenesis.

Tyrosine kinase and CD45 tyrosine phosphatase activity mediate p21ras activation in B cells stimulated through the antigen receptor

Cross-linking of the Ag receptor (AgR) induces intracellular signaling events in B cells, such as p21ras activation, that lead to their proliferation and differentiation. This event is accompanied by the tyrosine phosphorylation of the p21ras-associated GTPase-activating protein p120 ras.GAP, raising the possibility that AgR-stimulated p21ras activity is regulated by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPases) in B cells. To test this possibility, we examined the effects of PTK and PTPase inhibitors on protein tyrosine phosphorylation and p21ras activation induced by AgR cross-linking in TNP-specific TA3 7.9 murine B lymphoma cells. Although AgR-induced protein tyrosine phosphorylation was inhibited by the PTK inhibitors genistein and herbimycin A, it was enhanced by exposure to the PTPase inhibitor phenylarsine oxide (PAO). Cross-linking of the AgR by Ag or F(ab')2 anti-IgM induced a rapid (within 5 min) two- to threefold increase in p21ras activation in 7.9 B cells. Interestingly, a second peak of p21ras activation was evident at approximately 40 min after stimulation. Genistein and herbimycin A and PAO each blocked AgR-stimulated p21ras activation. Similarly, Ag-induced p21ras activation was inhibited by pretreatment of 7.9 B cells with an anti-CD45 mAb (detects the 220-kDa B cell isoform of CD45). Moreover, p21ras activation was induced by Ag and F(ab')2 anti-IgM in CD45+ but not CD45- J558L microns 3 B cells. These data indicate that p21ras activation induced by AgR cross-linking in B cells is regulated by both PTK and CD45 PTPase activities.

Tyrosine kinase and CD45 tyrosine phosphatase activity mediate p21ras activation in B cells stimulated through the antigen receptor

Cross-linking of the Ag receptor (AgR) induces intracellular signaling events in B cells, such as p21ras activation, that lead to their proliferation and differentiation. This event is accompanied by the tyrosine phosphorylation of the p21ras-associated GTPase-activating protein p120 ras.GAP, raising the possibility that AgR-stimulated p21ras activity is regulated by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPases) in B cells. To test this possibility, we examined the effects of PTK and PTPase inhibitors on protein tyrosine phosphorylation and p21ras activation induced by AgR cross-linking in TNP-specific TA3 7.9 murine B lymphoma cells. Although AgR-induced protein tyrosine phosphorylation was inhibited by the PTK inhibitors genistein and herbimycin A, it was enhanced by exposure to the PTPase inhibitor phenylarsine oxide (PAO). Cross-linking of the AgR by Ag or F(ab')2 anti-IgM induced a rapid (within 5 min) two- to threefold increase in p21ras activation in 7.9 B cells. Interestingly, a second peak of p21ras activation was evident at approximately 40 min after stimulation. Genistein and herbimycin A and PAO each blocked AgR-stimulated p21ras activation. Similarly, Ag-induced p21ras activation was inhibited by pretreatment of 7.9 B cells with an anti-CD45 mAb (detects the 220-kDa B cell isoform of CD45). Moreover, p21ras activation was induced by Ag and F(ab')2 anti-IgM in CD45+ but not CD45- J558L microns 3 B cells. These data indicate that p21ras activation induced by AgR cross-linking in B cells is regulated by both PTK and CD45 PTPase activities.

Antigen-induced B lymphocyte activation involves the p21ras and ras.GAP signaling pathway

Ligation of a B lymphocyte surface immunoglobulin (sIg) antigen receptor (AgR) by its specific Ag ligand initiates a signaling pathway that culminates in B cell activation. However, many events of this pathway have not been elucidated. Here we present three novel findings that demonstrate directly that AgR-mediated signaling in B cells functions by the p21ras/ras.GAP-dependent pathway. First, stimulation of TA3 7.9 Ag-specific murine B lymphoma cells for 2 min with either Ag or F(ab')2 anti-IgM induces p21ras activation as measured by an increase in the GTP/GDP ratio of its bound nucleotides. This activation of p21ras does not occur via a change in its guanine nucleotide exchange rate. Second, Ag stimulation results in the inhibition of activity of p120 ras.GAP, a protein that regulates p21ras activation. Tyrosine phosphorylation of ras.GAP occurs within 1 min after Ag stimulation but is no longer detectable at 20 min after stimulation, at which time ras.GAP activity remains inhibited. Thus, tyrosine phosphorylation of ras.GAP is not required for the inhibition of its activity. Third, despite the role proposed for a ras.GAP-associated p190 protein in the control of ras.GAP activity in B cells, p190 was not detectable either in anti-ras.GAP immunoprecipitates of [35S]methionine labeled lysates of Ag-stimulated or -unstimulated 7.9 cells or as a tyrosine phosphoprotein in Western blots of anti-ras.GAP immunoprecipitates of Ag-stimulated 7.9 cell lysates. Inasmuch as the TA3 7.9 B lymphoma is representative of a mature, sIgM-bearing B cell, our observations raise the intriguing possibility that the capacity of p190 to associate with ras.GAP and regulate the activities of ras.GAP and p21ras in a B cell is dependent on the stage of differentiation of the B cell.

Interleukin 4 reverses T cell proliferative unresponsiveness and prevents the onset of diabetes in nonobese diabetic mice

Beginning at the time of insulitis (7 wk of age), CD4+ and CD8+ mature thymocytes from nonobese diabetic (NOD) mice exhibit a proliferative unresponsiveness in vitro after T cell receptor (TCR) crosslinking. This unresponsiveness does not result from either insulitis or thymic involution and is long lasting, i.e., persists until diabetes onset (24 wk of age). We previously proposed that it represents a form of thymic T cell anergy that predisposes to diabetes onset. This hypothesis was tested in the present study by further investigating the mechanism responsible for NOD thymic T cell proliferative unresponsiveness and determining whether reversal of this unresponsiveness protects NOD mice from diabetes. Interleukin 4 (IL-4) secretion by thymocytes from > 7-wk-old NOD mice was virtually undetectable after treatment with either anti-TCR alpha/beta, anti-CD3, or Concanavalin A (Con A) compared with those by thymocytes from age- and sex-matched control BALB/c mice stimulated under identical conditions. NOD thymocytes stimulated by anti-TCR alpha/beta or anti-CD3 secreted less IL-2 than did similarly activated BALB/c thymocytes. However, since equivalent levels of IL-3 were secreted by Con A-activated NOD and BALB/c thymocytes, the unresponsiveness of NOD thymic T cells does not appear to be dependent on reduced IL-2 secretion. The surface density and dissociation constant of the high affinity IL-2 receptor of Con A-activated thymocytes from both strains are also similar. The patterns of unresponsiveness and lymphokine secretion seen in anti-TCR/CD3-activated NOD thymic T cells were also observed in activated NOD peripheral spleen T cells. Exogenous recombinant (r)IL-2 only partially reverses NOD thymocyte proliferative unresponsiveness to anti-CD3, and this is mediated by the inability of IL-2 to stimulate a complete IL-4 secretion response. In contrast, exogenous IL-4 reverses the unresponsiveness of both NOD thymic and peripheral T cells completely, and this is associated with the complete restoration of an IL-2 secretion response. Furthermore, the in vivo administration of rIL-4 to prediabetic NOD mice protects them from diabetes. Thus, the ability of rIL-4 to reverse completely the NOD thymic and peripheral T cell proliferative defect in vitro and protect against diabetes in vivo provides further support for a causal relationship between this T cell proliferative unresponsiveness and susceptibility to diabetes in NOD mice.

Thymic T cell anergy in autoimmune nonobese diabetic mice is mediated by deficient T cell receptor regulation of the pathway of p21ras activation

Thymic T cell anergy, as manifested by thymocyte proliferative unresponsiveness to antigens expressed in the thymic environment, is commonly believed to mediate the acquisition of immunological self-tolerance. However, we previously found that thymic T cell anergy may lead to the breakdown of tolerance and predispose to autoimmunity in nonobese diabetic (NOD) mice. Here, we show that NOD thymic T cell anergy, as revealed by proliferative unresponsiveness in vitro after stimulation through the T cell receptor (TCR), is associated with defective TCR-mediated signal transduction along the PKC/p21ras/p42mapk pathway of T cell activation. PKC activity is reduced in NOD thymocytes. Activation of p21ras is deficient in quiescent and stimulated NOD T cells, and this is correlated with a significant reduction in the tyrosine phosphorylation of p42mapk, a serine/threonine kinase active downstream of p21ras. Treatment of NOD T cells with a phorbol ester not only enhances their p21ras activity and p42mapk tyrosine phosphorylation but also restores their proliferative responsiveness. Since p42mapk activity is required for progression through to S phase of the cell cycle, our data suggest that reduced tyrosine phosphorylation of p42mapk in stimulated NOD T cells may abrogate its activity and elicit the proliferative unresponsiveness of these cells.

p21ras and protein kinase C function in distinct and interdependent signaling pathways in C3H 10T1/2 fibroblasts

Both p21ras and protein kinase C (PKC) are believed to function downstream of plasma membrane-associated tyrosine kinases in cellular signal transduction pathways. However, it has remained controversial whether they function in the same pathway and, if so, what their relative position and functional relationship in such a pathway are. We investigated the possibilities that p21ras and PKC function either upstream or downstream of each other in a common linear pathway or that they function independently in colinear signal pathways. Either decreased expression of endogenous normal ras in fibroblasts transfected with an inducible antisense ras construct or overexpression of a mutant ras gene reduced the capacity of the phorbol ester tetradecanoyl phorbol acetate to trigger expression of the tetradecanoyl phorbol acetate-responsive and ras-dependent reporter gene osteopontin (OPN). PKC depletion decreased basal OPN mRNA levels, and the overexpression of ras restored OPN expression to the level of non-PKC-depleted cells. We propose a model in which ras and PKC function in distinct and interdependent signaling pathways.