Health status and health care utilization after discharge from geriatric in-hospital stay - description of a register-based study.

BACKGROUND: This study is the first part of a register-based research program with the overall aim to increase the knowledge of the health status among geriatric patients and to identify risk factors for readmission in this population. The aim of this study was two-fold: 1) to evaluate the validity of the study cohorts in terms of health care utilization in relation to regional cohorts; 2) to describe the study cohorts in terms of health status and health care utilization after discharge. METHODS: The project consist of two cohorts with data from patient records of geriatric in-hospital stays, health care utilization data from Stockholm Regional Healthcare Data Warehouse 6 months after discharge, socioeconomic data from Statistics Sweden. The 2012 cohort include 6710 patients and the 2016 cohort, 8091 patients; 64% are women, mean age is 84 (SD 8). RESULTS: Mean days to first visit in primary care was 12 (23) and 10 (19) in the 2012 and 2016 cohort, respectively. Readmissions to hospital was 38% in 2012 and 39% in 2016. The validity of the study cohorts was evaluated by comparing them with regional cohorts. The study cohorts were comparable in most cases but there were some significant differences between the study cohorts and the regional cohorts, especially regarding amount and type of primary care. CONCLUSION: The study cohorts seem valid in terms of health care utilization compared to the regional cohorts regarding hospital care, but less so regarding primary care. This will be considered in the analyses and when interpreting data in future studies based on these study cohorts. Future studies will explore factors associated with health status and re-admissions in a population with multi-morbidity and disability.

Prediction of a time-sensitive condition among patients with dizziness assessed by the emergency medical services.

BACKGROUND: Dizziness is a relatively common symptom among patients who call for the emergency medical services (EMS). AIM: To identify factors of importance for the early identification of a time-sensitive condition behind the symptom of dizziness among patients assessed by the EMS. METHODS: All patients assessed by the EMS and triaged using Rapid Emergency Triage and Treatment (RETTS) for adults code 11 (=dizziness) in the 660,000 inhabitants in the Municipality of Gothenburg, Sweden, in 2016, were considered for inclusion. The patients were divided into two groups according to the final diagnosis (a time-sensitive condition, yes or no). RESULTS: There were 1536 patients who fulfilled the inclusion criteria, of which 96 (6.2%) had a time-sensitive condition. The majority of these had a stroke/transitory ischaemic attack (TIA). Eight predictors of a time-sensitive condition were identified. Three were associated with a reduced risk: 1) the dizziness was of a rotatory type, 2) the dizziness had a sudden onset and 3) increasing body temperature. Five were associated with an increased risk: 1) sudden onset of headache, 2) a history of head trauma, 3) symptoms of nausea or vomiting, 4) on treatment with anticoagulants and 5) increasing systolic blood pressure. CONCLUSION: Among 1536 patients who were triaged by the EMS for dizziness, 6.2% had a time-sensitive condition. On the arrival of the EMS, eight factors were associated with the risk of having a time-sensitive condition. All these factors were linked to the type of symptoms or to clinical findings on the arrival of the EMS or to the recent clinical history.

Adherence to the Healthy Nordic Food Index and the incidence of acute myocardial infarction and mortality among patients with stable angina pectoris.

BACKGROUND: The Healthy Nordic Food Index (HNFI) has been associated with beneficial effects on markers of cardiovascular disease (CVD). Whether such effects are present among patients with established coronary heart disease is unknown. In the present study, we investigated the association between adherence to the HNFI and the risk of acute myocardial infarction (AMI) (fatal or nonfatal) and death among patients with stable angina pectoris. METHODS: In the Western Norway B-vitamin Intervention Trial, participants completed a 169-item semi-quantitative food frequency questionnaire. The HNFI was calculated from six food groups (fish, cabbage, apples/pears, root vegetables, whole grain bread and oatmeal), scoring 0-6. Three adherence groups were defined: 0-1 points (low), 2-3 points (medium) or 4-6 points (high). Cox regression analyses investigated associations between adherence to the HNFI and outcomes. RESULTS: Among 2019 men (79.7%) and women with mean age of 61.7 years, 307 patients experienced an AMI event during a median (25th and 75th percentiles) follow-up of 7.5 (6.3 and 8.7) years. Median follow-up for total mortality was 10.5 (9.3 and 11.7) years; 171 patients died from CVD and 380 from any cause. No association between HNFI and the risk of AMI was detected. However, the HNFI was associated with a reduced risk of all-cause death, both by linear estimates [hazard ratio (95% confidence interval = 0.91 (0.84-0.98)] and by comparison of the highest with the lowest adherence group [hazard ratio (95% confidence interval = 0.70 (0.52-0.95)]. CONCLUSIONS: The results of the present study suggest that a Healthy Nordic diet may reduce mortality in patients with established CVD.

Sympathetic single axonal discharge after spinal cord injury in humans: activity at rest and after bladder stimulation.

STUDY DESIGN: Clinical experimental mechanistic study. OBJECTIVES: (1) To determine in three spinal cord-injured patients whether individual muscle sympathetic nerve fibres below the level of the spinal lesion display spontaneous activity. (2) To determine in these patients if individual sympathetic vasoconstrictor fibres show a prolonged discharge following a bladder stimulus. SETTING: University hospital in Gothenburg, Sweden. METHODS: Microneurographic recordings of action potentials from individual muscle nerve sympathetic fibres in a peroneal nerve. Recordings of skin blood flow and electrodermal responses in a foot. RESULTS: In all patients, there was sparse ongoing spontaneous impulse traffic in individual sympathetic fibres. Brisk mechanical pressure over the urinary bladder evoked a varying number of action potentials in individual fibres, but the activity was brief and did not continue after the end of the evoked multiunit burst. CONCLUSION: Prolonged discharges in individual sympathetic fibres are unlikely to contribute to a long duration of blood pressure increases induced by brief bladder stimuli.

Feasibility of endovascular and surface cooling strategies in acute stroke.

BACKGROUND: Therapeutic hypothermia (TH) is a promising treatment of stroke, but limited data are available regarding the safety and effectiveness of cooling methodology. We investigated the safety of TH and compared the cooling capacity of two widely used cooling strategies - endovascular and surface cooling. METHODS: COOLAID Oresund is a bicentre randomized trial in Copenhagen (Denmark) and Malmö (Sweden). Patients were randomized to either TH (33°C for 24 h) in a general intensive care unit (ICU) or standardized stroke unit care (control). Cooling was induced by a surface or endovascular-based strategy. RESULTS: Thirty-one patients were randomized. Seven were cooled using endovascular and 10 using surface-based cooling methods and 14 patients received standard care (controls). 14 (45%) patients received thrombolysis. Pneumonia was recorded in 6 (35%) TH patients and in 1 (7%) control. 4 TH patients and 1 control developed massive infarction. 1 TH patient and 2 control suffered asymptomatic haemorrhagic transformation. Mortality was comparable with 2 (12%) in the TH group and 1 (7%) among controls. Mean (SD) duration of hospital stay was 25.0 days (24, 9) in TH and 22.5 days (20.6) in control patients (P = 0.767). Mean (SD) induction period (cooling onset to target temperature) was 126.3 min (80.6) with endovascular cooling and 196.3 min (76.3) with surface cooling (P = 0.025). CONCLUSIONS: Therapeutic hypothermia with general anaesthesia is feasible in stroke patients. We noticed increased rates of pneumonia, while the length of hospital stay remained comparable. The endovascular cooling strategy provides a faster induction period than surface cooling.

Gluteal lymphoedema associated with lower extremity lymphoedema: A preliminary study with indocyanine green lymphography and magnetic resonance imaging.

INTRODUCTION: Indocyanine green (ICG) lymphography studies have identified that one in three to five patients with cancer-related lower extremity lymphoedema (LEL) demonstrated dermal backflow extending to the gluteal region. This study aimed to further characterize gluteal lymphoedema using contemporaneous magnetic resonance imaging (MRI). PATIENTS AND METHODS: Twenty-eight patients with unilateral advanced LEL who underwent both ICG lymphography and MRI prior to any surgical procedure were included in this study. The patients were divided into two groups with/without gluteal lymphoedema by the presence of dermal backflow on ICG lymphography. MRI was used to evaluate tissue changes. RESULTS: Ten patients demonstrated gluteal lymphoedema on ICG lymphography and had a higher incidence of skin hypertrophy in the gluteal region. However, no difference in excess leg volume was found between the two groups. A trend of increasing gluteal subcutaneous tissue in the affected side was identified in patients with gluteal lymphoedema with a median increase of 20% compared with an 11% increase in the non-gluteal lymphoedema group. The excess gluteal subcutaneous tissue was positively correlated to ipsilateral excess leg volume. CONCLUSION: The gluteal lymphoedema group on ICG lymphography had skin thickening in the gluteal region and was likely identified in the secondary cancer-related group. Surgical and conservative management options for gluteal lymphoedema need to be considered in advanced LEL.

Population-based cohort study of oral contraceptive use and risk of depression.

AIM: Research on the effect of oral contraceptive (OC) use on the risk of depression shows inconsistent findings, especially in adult OC users. One possible reason for this inconsistency is the omission of women who discontinue OCs due to adverse mood effects, leading to healthy user bias. To address this issue, we aim to estimate the risk of depression that is associated with the initiation of OCs as well as the effect of OC use on lifetime risk of depression. METHODS: This is a population-based cohort study based on data from 264,557 women from the UK Biobank. Incidence of depression was addressed via interviews, inpatient hospital or primary care data. The hazard ratio (HR) between OC use and incident depression was estimated by multivariable Cox regression with OC use as a time-varying exposure. To validate causality, we examined familial confounding in 7,354 sibling pairs. RESULTS: We observed that the first 2 years of OC use were associated with a higher rate of depression compared to never users (HR = 1.71, 95% confidence interval [CI]: 1.55-1.88). Although the risk was not as pronounced beyond the first 2 years, ever OC use was still associated with an increased lifetime risk of depression (HR = 1.05, 95% CI: 1.01-1.09). Previous OC use were associated with a higher rate of depression compared to never users, with adolescent OC users driving the increased hazard (HR = 1.18, 95% CI: 1.12-1.25). No significant association were observed among adult OC users who had previously used OCs (HR = 1.00, 95% CI: 0.95-1.04). Notably, the sibling analysis provided further evidence for a causal effect of OC use on the risk of depression. CONCLUSIONS: Our findings suggest that the use of OCs, particularly during the first 2 years, increases the risk of depression. Additionally, OC use during adolescence might increase the risk of depression later in life. Our results are consistent with a causal relationship between OC use and depression, as supported by the sibling analysis. This study highlights the importance of considering the healthy user bias as well as family-level confounding in studies of OC use and mental health outcomes. Physicians and patients should be aware of this potential risk when considering OCs, and individualized risk-benefit assessments should be conducted.

Muscle sympathetic response to arousal predicts neurovascular reactivity during mental stress.

Mental stress often begins with a sudden sensory (or internal) stimulus causing a brief arousal reaction, and is followed by a more long lasting stress phase. Both arousal and stress regularly induce blood pressure (BP) increases whereas effects on muscle sympathetic nerve activity (MSNA) are variable. Here we have compared responses of MSNA and BP during arousal induced by an electrical skin stimulus and mental stress evoked by a 3 min paced auditory serial arithmetic test (PASAT) in 30 healthy males aged 33 ± 10 years. In addition, recordings were made of ECG, respiratory movements, electrodermal activity and perceived stress. We also monitored corresponding effects of a cold test (CT: 2 min immersion of a hand in ice water). The arousal stimulus evoked significant inhibition of one or two MSNA bursts in 16 subjects, who were classified as responders; the remaining 14 subjects were non-responders. During mental stress responders showed a significant decrease of MSNA and a lesser BP increase compared to non-responders. In non-responders MSNA was unchanged or increased. Perceived stress was higher in non-responders (P = 0.056), but other measures were similar in the two groups. In non-responders mental stress and the cold test induced increases of BP that lasted throughout the subsequent rest period. During the cold test MSNA and BP increased equally in responders and non-responders. In the whole group of subjects, there was a significant correlation (r = 0.80, P < 0.001) between MSNA responses induced by arousal and by mental stress but not between responses evoked by arousal and the cold test (r < 0.1, P > 0.6). Additionally arousal-induced MSNA change was positively correlated with blood pressure changes during MS (systolic BP: r = 0.48; P < 0.01; diastolic BP: r = 0.42; P < 0.05) but not with blood pressure changes during CT. We conclude that in males the MSNA response to arousal predicts the MSNA and BP responses to mental stress.

Effect of the New Nordic Diet compared with usual care on glucose control in gestational diabetes mellitus: Study protocol for the randomized controlled trial intervention with new Nordic DIet in women with GestatiOnal diabetes mellitus (iNDIGO).

BACKGROUND: Gestational diabetes mellitus (GDM) is a pregnancy complication associated with short- and long-term health consequences for mother and child. First line treatment is diet and exercise but there is a recognized knowledge gap as to what diet treatment is optimal. A healthy Nordic diet has been associated with improved health but no studies in women with GDM exist. The New Nordic Diet (NND) is an initiative with the purpose to develop a healthy Nordic diet including foods with the potential to grow in Nordic countries; including fruit, berries, vegetables, whole-grain cereal products, nuts, fish, and rapeseed oil. The purpose of the intervention with new Nordic DIet in women with GestatiOnal diabetes mellitus (iNDIGO) is to test if the NND compared with usual care improves glucose control in women with GDM. METHODS: The iNDIGO study is a randomized parallel controlled trial where 50 women with GDM will be randomized to either an NND or usual care for 14 days (30-32 weeks of gestation). Participants in the NND group will receive menus and food bags containing foods to be consumed. Primary outcome is glycemic control (time in target) measured using continuous glucose monitoring. Compliance to the dietary intervention will be tested using dietary biomarkers and adherence questionnaires. CONCLUSION: Diet treatment represents first line treatment in GDM but it remains unclear what type of diets are effective. iNDIGO is an efficacy study and will provide evidence as to whether a healthy Nordic diet can improve glucose control in women with GDM. TRIAL REGISTRATION: ClinicalTrials.gov registration Number: NCT04169243. Registered 19 November 2019, https://clinicaltrials.gov/ct2/show/NCT04169243.

Right-hemispheric brain activation correlates to language performance.

Language function in the right-hemispheric homologues of Broca's and Wernicke's areas does not only correlate with left-handedness or pathology, but occurs naturally in right-handed healthy subjects as well. In the current study, two non-invasive methods of assessing language lateralization are correlated with behavioral results in order to link hemispheric dominance to language ability in healthy subjects. Functional magnetic resonance imaging (fMRI) together with a sentence-completion paradigm was used to determine region-specific lateralization indices in the left- and right-sided Broca's and Wernicke's areas, the frontal temporal lobe, the anterior cingulate cortex and the parietal lobe. In addition, dichotic listening results were used to determine overall language lateralization and to strengthen conclusions by correlating with fMRI indices. Results showed that fMRI lateralization in the superior parietal, the posterior temporal, and the anterior cingulate cortices correlated to dichotic listening. A decreased right ear advantage (REA), which indicates less left-hemispheric dominance in language, correlated with higher performance in most administered language tasks, including reading, language ability, fluency, and non-word discrimination. Furthermore, right hemispheric involvement in the posterior temporal lobe and the homologue of Broca's area suggests better performance in behavioral language tasks. This strongly indicates a supportive role of the right-hemispheric counterparts of Broca's and Wernicke's areas in language performance.

Quantitative HHV-6B antigenemia test for the monitoring of transplant patients.

Human herpesvirus-6 (HHV-6) infection, mostly caused by variant B, is common after transplantation. Here, we report a new modified method using an HHV-6B glycoprotein IgG antibody, OHV-3, and attempt to quantify the HHV-6 antigenemia after liver transplantation. Twenty-four liver transplant recipients were frequently monitored by the HHV-6 antigenemia test, which detects the HHV-6B virion protein in peripheral blood mononuclear cells (PBMC). HHV-6B antigens were now retrospectively demonstrated using a glycoprotein OHV-3 IgG antibody in the immunoperoxidase staining from the same specimens and quantified as positive cells/10,000 PBMC. The results were confirmed and quantified by DNA hybridization in situ. Altogether, 206 blood specimens were analyzed. During the first six months, HHV-6 antigenemia was detected in 17/24 (71%) recipients by using the HHV-6B virion antibody. In total, 37% (77/206) of specimens were positive with the virion antibody and 39% (78/201) by the OHV-3 antibody. The peak number of OHV-3-positive cells in the PBMC varied from 5 to 750/10,000 (mean 140/10,000). The OHV-3 antibody was useful to quantify the HHV-6B antigenemia. The findings of the HHV-6B quantitative antigenemia using the OHV-3 antibody correlated well with the previous qualitative HHV-6 antigenemia assay, and can be used as an alternative quantitative method in the monitoring of HHV-6 in transplant patients.

Out-of-hospital cardiac arrest: Causes according to autopsy and electrocardiography - Analysis of 781 patients with neither hospital care nor prescribed medication during the preceding two years.

BACKGROUND: There is a knowledge gap regarding aetiology of and potential for predicting out-of-hospital cardiac arrest (OHCA) among individuals who are healthy before the event. AIM: To describe causes of OHCA and the potential for predicting OHCA in apparently healthy patients. METHODS: Patients were recruited from the Swedish Register of Cardiopulmonary Resuscitation from November 2007 to January 2011. Inclusion criteria were: OHCA with attempted CPR but neither dispensed prescription medication nor hospital care two years before the event The register includes the majority of patients suffering OHCA in Sweden where cardiopulmonary resuscitation (CPR) was attempted. Medication status was defined by linkage to the Swedish Prescribed Drug Register. Cause of death was assessed based on autopsy and the Swedish Cause of Death Register. Prediction of OHCA was attempted based on available electrocardiograms (ECG) before the OHCA event. RESULTS: Altogether 781 individuals (16% women) fulfilled the inclusion criteria. Survival to 30 days was 16%. Autopsy rate was 72%. Based on autopsy, 70% had a cardiovascular aetiology and 59% a cardiac aetiology. An ECG recording before the event was found in 23% of cases. The ECG was abnormal in 22% of them. CONCLUSION: Among OHCA victims who appeared to be healthy prior to the event, the cause was cardiovascular in the great majority according to autopsy findings. A minority had a preceding abnormal ECG that could have been helpful in avoiding the event.

Investigation of self-reported dizziness in the elderly when lying down or turning over in bed, and possible benign paroxysmal positional vertigo.

OBJECTIVES: This study aimed to investigate the rate of dizziness and occurrence of benign paroxysmal positional vertigo in the elderly by physical examination in those reporting dizziness symptoms when lying down or turning over in bed. METHODS: A total of 498 people, aged 70-85 years, were asked to complete a questionnaire regarding dizziness symptoms. Subjects answering that they became dizzy in bed were asked to participate in a physical examination and diagnostic manoeuvres investigating benign paroxysmal positional vertigo. RESULTS: A total of 324 participants (65 per cent) completed the questionnaire. More than one-quarter (29 per cent) reported dizziness and 32 (10 per cent) reported dizziness when turning in bed. Of these 32 persons, 22 (69 per cent) underwent a physical examination. Six participants tested positive for benign paroxysmal positional vertigo. CONCLUSION: Ten per cent of the elderly participants reported positional symptoms, and 6 out of 22 fulfilled diagnostic criteria for benign paroxysmal positional vertigo. Furthermore, benign paroxysmal positional vertigo was established despite a delay between questionnaire completion and investigation, emphasising that this type of dizziness may not be a self-limiting disorder.

Sustainability of an Enhanced Recovery Program for Pancreaticoduodenectomy with Pancreaticogastrostomy.

BACKGROUND:: Enhanced recovery program for pancreaticoduodenectomy have become standard care. Little is known about adherence rates and sustainability of the program, especially when pancreaticogastrostomy is used in reconstruction. The aim of this study was, therefore, to evaluate adherence rates and continued outcome, after implementation of an enhanced recovery program. METHODS:: Consecutive patients undergoing pancreaticoduodenectomy at the Department of Surgery, Skåne University Hospital, Lund, Sweden were followed, after implementation of enhanced recovery program, October 2012. In April 2015, some items in the enhanced recovery program were modified, namely earlier removal of nasogastric tubes and abdominal drain. The patients were analyzed in three groups, the implementation group (control) and two post-implementation groups; intermediate and modified group. Sustainability was assessed according to length of stay and adherence rate. RESULTS:: In total, 160 patients were identified. The overall protocol adherence rate increased from 65% to 72%, p = 0.035. While the pre- and intraoperative protocol items were fulfilled to more than >90%, the postoperative were lower, but increasing over time; 48%, 50%, and 58%, p = 0.033. Postoperative complications and hospital length of stay did not change significantly. CONCLUSION:: The positive outcome of an enhanced recovery program for pancreaticoduodenectomy was reasonably well sustained. Compliance with the protocol has increased, but strict adherence remains a challenge, especially with the postoperative items.

Addition of intravenous iron to epoetin beta increases hemoglobin response and decreases epoetin dose requirement in anemic patients with lymphoproliferative malignancies: a randomized multicenter study.

This randomized study assessed if intravenous iron improves hemoglobin (Hb) response and permits decreased epoetin dose in anemic (Hb 9-11 g/dl), transfusion-independent patients with stainable iron in the bone marrow and lymphoproliferative malignancies not receiving chemotherapy. Patients (n=67) were randomized to subcutaneous epoetin beta 30 000 IU once weekly for 16 weeks with or without concomitant intravenous iron supplementation. There was a significantly (P<0.05) greater increase in mean Hb from week 8 onwards in the iron group and the percentage of patients with Hb increase >or=2 g/dl was significantly higher in the iron group (93%) than in the no-iron group (53%) (per-protocol population; P=0.001). Higher serum ferritin and transferrin saturation in the iron group indicated that iron availability accounted for the Hb response difference. The mean weekly patient epoetin dose was significantly lower after 13 weeks of therapy (P=0.029) and after 15 weeks approximately 10 000 IU (>25%) lower in the iron group, as was the total epoetin dose (P=0.051). In conclusion, the Hb increase and response rate were significantly greater with the addition of intravenous iron to epoetin treatment in iron-replete patients and a lower dose of epoetin was required.

Survival and neurological outcome in the elderly after in-hospital cardiac arrest.

BACKGROUND: There have been few studies of the outcome in elderly patients who have suffered in-hospital cardiac arrest (IHCA) and the association between cardiac arrest characteristics and survival. AIM: The aim of this large observational study was to investigate the survival and neurological outcome in the elderly after IHCA, and to identify which factors were associated with survival. METHODS: We investigated elderly IHCA patients (≥70years of age) who were registered in the Swedish Cardiopulmonary Resuscitation Registry 2007-2015. For descriptive purposes, the patients were grouped according to age (70-79, 80-89, and ≥90years). Predictors of 30-day survival were identified using multivariable analysis. RESULTS: Altogether, 11,396 patients were included in the study. Thirty-day survival was 28% for patients aged 70-79 years, 20% for patients aged 80-89 years, and 14% for patients aged ≥90years. Factors associated with higher survival were: patients with an initially shockable rhythm, IHCA at an ECG-monitored location, IHCA was witnessed, IHCA during daytime (8 a.m.-8 p.m.), and an etiology of arrhythmia. A lower survival was associated with a history of heart failure, respiratory insufficiency, renal dysfunction and with an etiology of acute pulmonary oedema. Patients over 90 years of age with VF/VT as initial rhythm had a 41% survival rate. We found a trend indicating a less aggressive care with increasing age during cardiac arrest (fewer intubations, and less use of adrenalin and anti-arrhythmic drugs) but there was no association between age and delay in starting cardiopulmonary resuscitation (CPR). In survivors, there was no significant association between age and a favourable neurological outcome (CPC score: 1-2) (92%, 93%, and 88% in the three age groups, respectively). CONCLUSIONS: Increasing age among the elderly is associated with a lower 30-day survival after IHCA. Less aggressive treatment and a worse risk profile might contribute to these findings. Relatively high survival rates among certain subgroups suggest that discussions about advanced directives should be individualized. Most survivors have good neurological outcome, even patients over 90 years of age.

Apoptosis of NIH3T3 cells overexpressing the Src homology 2 domain protein Shb.

To understand the role of the Src homology 2 (SH2) domain protein Shb in the signal transduction of tyrosine kinase receptor, NIH3T3 cells were transfected with a DNA construct expressing the Shb cDNA (NIHSHB cells). The NIHSHB cells expressed elevated levels of proteins with the estimated molecular weights of 77, 66 and 55 kDa as determined by immunoblotting. In contrast to the control cells, the NIHSHB cells failed to increase in cell number in the presence of 1% serum. This effect was largely due to apoptosis, since staining of pyknotic nuclei was observed using the terminal transferase labeling method. The NIHSHB cells displayed similar levels of c-myc mRNA and decreased contents of the p53 protein after culture in 1% serum compared with control cells. The addition of platelet-derived growth factor (PDGF-BB) restored the growth of the NIHSHB cells, whereas insulin-like growth factor-1 (IGF-1) failed to affect the proliferation of Shb overexpressing cells in 1% serum. We conclude that Shb overexpression is associated with cell degeneration under certain conditions, and that Shb could transduce apoptotic signals from tyrosine kinase receptors.

Shb is a ubiquitously expressed Src homology 2 protein.

To identify serum-inducible genes in the insulin-producing cell line beta TC-1, a library subtraction screening procedure was performed on serum-deprived (G0) and serum-restimulated (G1) insulin-producing beta TC-1 cells. A cDNA containing a motif with strong homology to Src homology 2 (SH2) domains was found using this procedure and called Shb. The Shb cDNA contains two methionine codons in its N-terminus and thus may code for two proteins of 67 and 56 kDa, each with one SH2 domain in its C-terminus. No other structural similarity to proteins with catalytic activity could be detected, suggesting that Shb is a so called adaptor. Shb contains the proline-rich sequence PPPGPGR between the two proposed initiator methionines which resembles a sequence for binding to Src homology 3 (SH3) domains. A second proline-rich sequence was detected after the second methionine codon. The Shb cDNA hybridized to a similar or identical mRNA of 3.1 kb expressed in mouse brain, liver, kidney, heart, NIH3T3 fibroblasts and beta TC-1 cells. Western blot analysis of the same tissues using an antiserum directed against a synthetic peptide corresponding to a part of the SH2 domain of Shb, revealed reactivity with two proteins of 56 and 67 kDa. In addition, a third reactive component of 40 kDa was detected in most tissues. Transfection and transient expression of the Shb cDNA in COS-1 cells yielded increased expression of the 67, 56 and 40 kDa proteins. Transfection and stable expression of the Shb cDNA in pig aortic endothelial cells showed increased expression primarily of the 67 kDa protein. A fusion protein consisting of the SH2 domain of Shb linked to glutathione S-transferase showed increased binding to glycoproteins of cells stimulated with platelet-derived growth factor (PDGF-BB). Furthermore, the autophosphorylated PDGF beta-receptor but not the autophosphorylated epidermal growth factor (EGF) receptor bound specifically to immobilized fusion protein. It is concluded that Shb is a novel SH2-containing protein with proline-rich domains and therefore probably involved in the signal-transduction of some ligand-activated tyrosine kinase receptors.

Molecular interactions of the Src homology 2 domain protein Shb with phosphotyrosine residues, tyrosine kinase receptors and Src homology 3 domain proteins.

The molecular interactions of the Src homology 2 (SH2) domain and the N-terminal proline-rich sequence motifs (pro-1 to pro-5) of the SH2 protein Shb with other components were presently characterised. Using a degenerate phosphopeptide library the preferred binding site for the Shb SH2 domain was determined to pTyr-Thr/Val/Ile-X-Leu at positions +1 to +3 relative the phosphotyrosine residue. Experiments with competing peptides and platelet-derived growth factor (PDGF) beta-receptor mutants with Y to F substitutions in autophosphorylation sites revealed multiple binding sites for the Shb SH2 domain in the receptor. The Shb SH2 domain also binds to in vitro phosphorylated fibroblast growth factor receptor-1 (FGFR-1) mainly through position Y776. The receptor experiments suggest that other residues besides the +1 to +3 positions may also be of significance for Shb binding. The pro-4/pro-5 motif of Shb binds in vitro particularly well to the Src, p85 alpha PI3-kinase and Eps8 SH3 domains expressed as GST fusion proteins. However, the GST-SH3 domain fusion proteins tested bind in vitro to peptides corresponding to the pro-1 to pro-5 motifs of Shb with low affinity and selectivity, suggesting that sequences outside the core proline motif may also be important for Shb-SH3 domain interactions. In vivo association between Shb-SH3 domain proteins v-Src and Eps8 was detected by coimmunoprecipitation. PDGF treatment did not affect the association between Eps8 and Shb. The data suggest that Shb is an adaptor protein linking SH3 domain proteins to tyrosine kinases or other tyrosine phosphorylated proteins.

Stimulation through the T cell receptor leads to interactions between SHB and several signaling proteins.

Shb is a recently described Src homology 2 (SH2) domain-containing adaptor protein. Here we show that Shb is expressed in lymphoid tissues, and is recruited into signaling complexes upon activation of Jurkat T cells. Grb2 binds proline-rich motifs in Shb via its SH3 domains. As a result, a number of proteins detected in anti-Shb and anti-Grb2 immunoprecipitates are shared, including phosphoproteins of 22, 36/38, 55/57 and 70 kDa. Shb-association with p22, which represents the T cell receptor associated zeta chain, occurs through the Shb SH2 domain. The central region of Shb binds p36/38. Since this interaction was inhibited by phosphotyrosine, this region of Shb is likely to contain a non-SH2 PTB (phosphotyrosine binding) domain. The Shb PTB domain was found to preferentially bind the sequence Asp-Asp-X-pTyr when incubated with a phosphopeptide library. A peptide corresponding to a phosphorylation site in 34 kDa Lnk inhibited association between Shb and p36/38. Overexpression of Shb in Jurkat cells led to increased basal phosphorylation of Shb-associated p36/38 and p70 proteins. Inactivation of the Shb SH2 domain by an R522K mutation resulted in a reduced stimulation of tyrosine phosphorylation of several proteins in response to CD3 crosslinking when expressed in Jurkat cells. Together, our results show three distinct domains of Shb all participate in the formulation of multimeric signaling complexes in activated T cells. These results indicate that the Shb protein functions in T cell receptor signaling.