Whakawhanaungatanga-Building trust and connections: A qualitative study indigenous Māori patients and whānau (extended family network) hospital experiences

AIMS

Investigated the experiences of Māori (the Indigenous peoples of Aotearoa, New Zealand) patients and whānau (extended family network) engaging with acute hospital inpatient services and their priorities for a Māori-centred model of relational care.

DESIGN

A qualitative Māori-centred research design using a Thought Space Wānanga (learning through in-depth group discussion, deliberation and consideration) approach.

METHODS

Two wānanga were conducted between May 2022 and June 2022, with 13 Māori patients who had been acutely hospitalized within the past 12 months and their whānau members. The first wānanga utilized storytelling and journey mapping to collect data. The second wānanga refined the initial themes. Wānanga were audio-recorded and then inductively coded and developed into themes.

RESULTS

Thirteen patients and whānau attended the first wānanga, while 10 patients and whānau participated in the second wānanga). Four themes were developed: (1) Whakawhanaungatanga (establishing connections and relationships), (2) Whakamana (uplifting the status and esteem of Māori), (3) Whakawhitiwhiti kōrero (the importance of communicating, discussing and deliberating) and (4) Kotahitanga (working together with purpose) all provide insights into the importance of effectively engaging and connecting with Māori patients and whānau when acutely hospitalized.

CONCLUSIONS

The experiences and priorities of Māori patients and whānau affirm the international literature, suggesting that Indigenous relational concepts are critical to building relationships, connections and trust. Despite existing healthcare models for working with Indigenous peoples, their poor application contributes to sub-optimal healthcare experiences at all points of their healthcare journey. A relational mode of practice focused on engagement and forming connections better meets the needs of Indigenous peoples engaging with inpatient health services.

IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE

Despite the existence of Indigenous models of care, Indigenous peoples consistently report a lack of engagement and connection when accessing inpatient health services. Without establishing relationships, applying models of care is challenging.

IMPACT (ADDRESSING)

What problem did the study address? Internationally, healthcare systems are consistently ill-equipped to deliver culturally safe care for Indigenous and marginalized peoples, evident in ongoing health inequities. Like other reports of Indigenous experiences of health services, Māori express dissatisfaction with care delivery in an acute inpatient setting. This study investigated Māori patients and whānau experiences engaging with acute hospital inpatient services and their priorities for a Māori-centred model of relational care. What were the main findings? Māori patients and whānau recounted negative experiences with healthcare professionals lacking effective relationships and trust. Satisfaction occurred when engagement with health care professionals resembled Indigenous cultural rituals of encounter that considered their holistic, collective and dynamic worldviews. Previous models of relational care, while helpful, are not Indigenous and so do not address their needs, such as engagement as a mode of practice (how) to achieve this. Where and on whom will the research have an impact? This research impacts Indigenous peoples' health outcomes, particularly Māori, and nurses and clinicians working and interacting within acute inpatient and other hospital settings. Indigenous research methods support co-constructing knowledge for translation into practical outcomes through transformational practices, policies and theory development.

REPORTING METHOD

We used the Consolidated Criteria for Strengthening the Reporting of Health Research Involving Indigenous Peoples (CONSIDER) statement (see File S2-CONSIDER Checklist) and the Consolidated Criteria for Reporting Qualitative Research (COREQ) guidelines (see File S3-COREQ Checklist).

PATIENT OR PUBLIC CONTRIBUTION

Māori patients and their whānau interviewed about their experiences were involved in data interpretation.

Psychological impact of acne on 21st-century adolescents: decoding for better care

The psychological consequences of acne have been the subject of many studies. As a particularly visible skin disorder, acne complicates the daily lives of adolescents who are undergoing multiple transformations: physical, intellectual and emotional. While it is well established that acne can be responsible for depression and low self-esteem, it is likely that this impact is aggravated by the sociological evolution of adolescents in the 21st century. Understanding the codes of adolescents today (who can be characterized as being more concerned by their appearance than previous generations at the same age) allows us to optimize our medical approach to acne and facilitates treatment compliance and adherence.

Linac4 low energy beam measurements with negative hydrogen ions

Linac4, a 160 MeV normal-conducting H(-) linear accelerator, is the first step in the upgrade of the beam intensity available from the LHC proton injectors at CERN. The Linac4 Low Energy Beam Transport (LEBT) line from the pulsed 2 MHz RF driven ion source, to the 352 MHz RFQ (Radiofrequency Quadrupole) has been built and installed at a test stand, and has been used to transport and match to the RFQ a pulsed 14 mA H(-) beam at 45 keV. A temporary slit-and-grid emittance measurement system has been put in place to characterize the beam delivered to the RFQ. In this paper a description of the LEBT and its beam diagnostics is given, and the results of beam emittance measurements and beam transmission measurements through the RFQ are compared with the expectation from simulations.

Electrostatics of cell membrane recognition: structure and activity of neutral and cationic rigid push-pull rods in isoelectric, anionic, and polarized lipid bilayer membranes

Design, synthesis, and structural and functional studies of rigid-rod ionophores of different axial electrostatic asymmetry are reported. The employed design strategy emphasized presence of (a) a rigid scaffold to minimize the conformational complexity, (b) a unimolecular ion-conducting pathway to minimize the suprastructural complexity and monitor the function, (c) an extended fluorophore to monitor structure, (d) variable axial rod dipole, and (e) variable terminal charges to create axial asymmetry. Studies in isoelectric, anionic, and polarized bilayer membranes confirmed a general increase in activity of uncharged rigid push-pull rods in polarized bilayers. The similarly increased activity of cationic rigid push-pull rods with an electrostatic asymmetry comparable to that of alpha-helical bee toxin melittin (positive charge near negative axial dipole terminus) is shown by fluorescence-depth quenching experiments to originate from the stabilization of transmembrane rod orientation by the membrane potential. The reduced activity of rigid push-pull rods having an electrostatic asymmetry comparable to that in alpha-helical natural antibiotics (a positive charge near the positive axial dipole terminus) is shown by structural studies to originate from rod "ejection" by membrane potentials comparable to that found in mammalian plasma membranes. This structural evidence for cell membrane recognition by asymmetric rods is unprecedented and of possible practical importance with regard to antibiotic resistance.

Electrostatics of cell membrane recognition: structure and activity of neutral and cationic rigid push-pull rods in isoelectric, anionic, and polarized lipid bilayer membranes

Design, synthesis, and structural and functional studies of rigid-rod ionophores of different axial electrostatic asymmetry are reported. The employed design strategy emphasized presence of (a) a rigid scaffold to minimize the conformational complexity, (b) a unimolecular ion-conducting pathway to minimize the suprastructural complexity and monitor the function, (c) an extended fluorophore to monitor structure, (d) variable axial rod dipole, and (e) variable terminal charges to create axial asymmetry. Studies in isoelectric, anionic, and polarized bilayer membranes confirmed a general increase in activity of uncharged rigid push-pull rods in polarized bilayers. The similarly increased activity of cationic rigid push-pull rods with an electrostatic asymmetry comparable to that of alpha-helical bee toxin melittin (positive charge near negative axial dipole terminus) is shown by fluorescence-depth quenching experiments to originate from the stabilization of transmembrane rod orientation by the membrane potential. The reduced activity of rigid push-pull rods having an electrostatic asymmetry comparable to that in alpha-helical natural antibiotics (a positive charge near the positive axial dipole terminus) is shown by structural studies to originate from rod "ejection" by membrane potentials comparable to that found in mammalian plasma membranes. This structural evidence for cell membrane recognition by asymmetric rods is unprecedented and of possible practical importance with regard to antibiotic resistance.

Variations in susceptibility to proteoglycan-induced arthritis and spondylitis among C3H substrains of mice: evidence of genetically acquired resistance to autoimmune disease

OBJECTIVE

To identify and screen the level of arthritis susceptibility in C3H murine strains known to be resistant to proteoglycan (aggrecan)-induced arthritis, and to measure and correlate various immunologic and inflammatory parameters with susceptibility to either arthritis or spondylitis in various C3H substrains.

METHODS

Mice of 10 C3H substrains (subcolonies) were immunized with cartilage proteoglycan (aggrecan) for induction of arthritis. Animals were assessed for clinical symptoms, and the peripheral joints and spine were studied by histologic methods. Proteoglycan-specific T cell responses (T cell proliferation and production of interleukin-2 [IL-2], interferon-y, and IL-4) and the B cell response to lipopolysaccharide (LPS) were measured in spleen cell cultures. Serum levels of heteroantibodies and autoantibodies as well as various cytokines (IL-6, IL-10, IL-12, and tumor necrosis factor alpha) and soluble CD44 were determined by enzyme-linked immunosorbent assay.

RESULTS

Immunization with cartilage proteoglycan induced severe arthritis in the C3H/HeJCr substrain (95-100% incidence), whereas the original parent mice of the C3H/HeJ colony were resistant to proteoglycan (aggrecan)-induced arthritis. Furthermore, the progressive polyarthritis that is characteristic in susceptible C3H/HeJCr mice was accompanied by progressive inflammation around the spine. In subsequent experiments, 10 different C3H colonies with largely identical genetic backgrounds (all originating from the National Institutes of Health or Jackson Laboratory) exhibited extreme differences in susceptibility. Although none of the laboratory findings, including LPS hyporesponsiveness, immunologic parameters, and inflammatory markers, showed a correlation with susceptibility or resistance in the C3H/HeJCr and C3H/HeJ substrains, respectively, significant differences were found when all arthritic C3H mice were compared with all nonarthritic animals, regardless of their substrain origin.

CONCLUSION

Because many of the C3H substrains lost arthritis susceptibility or acquired resistance, our results suggest that a preferred site for a mutation(s) in a gene(s) in a relatively upstream position of the inflammatory cascade is present. This is the first autoimmune model that exhibits extreme differences in arthritis susceptibility in the same murine strain, and is therefore a valuable tool for identification of arthritis-susceptible (or arthritis-suppressive) genes.

What is the schizophrenic patients' level of information about their disease and their treatment?

Improved compliance with antipsychotic medication is a major issue in schizophrenic management. For this purpose educational programs have been used, but up to now, little or no information has been gathered or published in France concerning schizophrenic patients' opinion on information they have about their disease and their treatment. Thus we conducted a survey in concert with 78 psychiatrists from the French psychiatric health service. From this cross sectional survey we assessed 336 outpatients (male: 72%; mean age: 36 +/- 10.4 years) with schizophrenia according to the DSM IV (paranoid sub type: 57%, disorganized: 12%, catatonic: 1%, undifferentiated: 12%, residual: 18%). The mean duration of the illness was 11.6 years (sd: 8.5) and the mean duration of the follow up with the same psychiatrist was 5.4 years (sd: 5.1). Patients completed a questionnaire which assessed their level of information on mental illness and treatment. The diagnosis of schizophrenia has been told to their patients by 39% of the psychiatrists, and treatment has been explained to the patients by 96% of the practitioners. Results indicate less than half of the patients (45%) felt ill, only 46% thought they knew their illness well or very well (nevertheless only 31% of them named spontaneously the diagnosis of schizophrenia or psychosis), and 61% considered that they had been given sufficient information. Most of the patients (79%) were persuaded that their treatment was useful, and 75% of patients were completely satisfied with their treatment. Surprisingly 92% reported taking their medication regularly. Most patients think that a high level of information about their illness (74%) and treatment (79%) help them to cope better with their schizophrenia. Analysis performed according to patients characteristics indicated that paranoid patients felt more ill (p = 0.035) than others, thought to know less about their illness (p = 0.0065), and were less satisfied with their treatment (p = 0.04) and their level of information (p = 0.03). Patients with a duration of their illness longer than 10 years were more convinced of the utility of their treatment (p = 0.02) and had debated more on the choice of their treatment with their psychiatrist (p = 0.047). Patients older than 35 years were more satisfied with their information (p = 0.002). More patients with atypical antipsychotics accepted to take their treatment on a regular basis (p = 0.035) compared to patients under classical neuroleptics. This survey underlines that mental health consumers' opinions can be obtained even in the field of schizophrenia, and argues in favour of further such investigations. It also highlights the need for educational programs on schizophrenia and antipsychotic medications.

[What information do patients with schizophrenia have about their illness and treatment?]

Improved compliance with antipsychotic medication is a major issue in schizophrenic management. For this purpose educational programs have been used, but up to now, little or no information has been gathered or published in France concerning schizophrenic patients' opinion on information they have about their disease and their treatment. Thus we conducted a survey in concert with 78 psychiatrists from the French psychiatric health service. From this cross sectional survey we assessed 336 outpatients (male: 72%; mean age: 36 +/- 10.4 years) with schizophrenia according to the DSM IV (paranoid sub type: 57%, disorganized: 12%, catatonic: 1%, undifferentiated: 12%, residual: 18%). The mean duration of the illness was 11.6 years (sd: 8.5) and the mean duration of the follow up with the same psychiatrist was 5.4 years (sd: 5.1). Patients completed a questionnaire which assessed their level of information on mental illness and treatment. The diagnosis of schizophrenia has been told to their patients by 39% of the psychiatrists, and treatment has been explained to the patients by 96% of the practitioners. Results indicate less than half of the patients (45%) felt ill, only 46% thought they knew their illness well or very well (nevertheless only 31% of them named spontaneously the diagnosis of schizophrenia or psychosis), and 61% considered that they had been given sufficient information. Most of the patients (79%) were persuaded that their treatment was useful, and 75% of patient were completely satisfied with their treatment. Surprisingly 92% reported taking their medication regularly. Most patients think that a high level of information about their illness (74%) and treatment (79%) help them to cope better with their schizophrenia. Analysis performed according to patients characteristics indicated that paranoid patients felt more ill (p = 0.035) than others, thought to know less about their illness (p = 0.0065), and were less satisfied with their treatment (p = 0.04) and their level of information (p = 0.03). Patients with a duration of their illness longer than 10 years were more convinced of the utility of their treatment (p = 0.02) and had debated more on the choice of their treatment with their psychiatrist (p = 0.047). Patients older than 35 years were more satisfied with their information (p = 0.002). More patients with atypical antipsychotics accepted to take their treatment on a regular basis (p = 0.035) compared to patients under classical neuroleptics. This survey underlines that mental health consumers' opinions can be obtained even in the field of schizophrenia, and argues in favour of further such investigations. It also highlights the need for educational programs on schizophrenia and antipsychotic medications.

[Sulpiride: study of 669 patient presenting with pain of psychological origin]

Among somatoform disorders, pain disorder (DSM IV) appears to be relatively common in general practice and to cause social, psychological, and functional impairment. A previous study conducted by Lemoine (1997) has shown that sulpiride is more effective than placebo in reducing intensity and frequency of pain in this disorder. The aim of our study was to assess safety and efficacy of sulpiride in a large sample of patients under natural conditions of use, in general practice. In a multicenter, open clinical trial, 669 patients (mean age: 47 years +/- 12; male: 245, female: 424) fulfilling the DSM IV criteria for pain disorder (of gastrointestinal localization), were included by 321 general practitioners (GP) and treated for 6 weeks with sulpiride 150 mg/d. Investigators' evaluations were planned at D14 and D42. Furthermore a diary was given to each patient for self evaluation and intercurrent events reporting. The pain was of psychological type in 93% of cases and caused social or working disabilities in 78% of patients. At inclusion the mean score of the Hamilton Anxiety Rating Scale was 18 +/- 8, and the mean score of the depression scale HARD (Humeur, Angoisse, Ralentissement, Danger) was 14.8 +/- 6.4. During the study 7.9% of the patients had at least one adverse event, and 3% of patients were withdrawn for adverse event. Safety assessed with a specific variable (grouping together adverse events' reporting and results of CGI item 3) was good for 88% of patients. The principal criterion of efficacy was the clinician's evaluation of the intensity and frequency of abdominal pain on a four-point scale from 0 (asymptomatic) to 3 (important/continuous) from D0 to D End a decrease in pain intensity (91% of patients) and in pain frequency (89%) was observed as well as in frequency and intensity of related gastroenterological symptoms such as disturbances of bowel movements (79% and 78%), bloated symptoms (88% and 83%), nausea/vomiting (90% and 90%). A similar improvement (p < 0.001) was observed from D0 to End point on the self evaluation parameters (Visual Analogic Scales), assessing pain (mean score D0-D End: 17.1 +/- 15.9), quality of sleep (mean score D0-D End: 27.1 +/- 17.8), activity (mean score D0-D End: 24.4 +/- 18.8), and appetite (mean score D0-D End: 22.6 +/- 16.6). In conclusion these results confirm the usefulness of sulpiride in the treatment of pain disorders a symptomatology known to cause difficulties to GP's in their practice.

[Causes and consequences of elderly's agitated and aggressive behavior]

Agitation and aggressiveness are frequent in the elderly and often related to dementia. As a result of the ageing of the general population this is becoming a major public health concern. No or little epidemiological data, during primary health care, about symptoms, co-morbidity, nor medical and social consequences of elderlys' disruptive behavior have been gathered or published in the French literature. Thus, in order to describe these disorders, a survey in cooperation with general practitioners (GP) was conducted. A representative sample of 212 French GP's, all with preferential geriatric activity were asked to conduct a study by including retrospectively their two most recent patients older than 65, who had exhibited agitation and/or aggressiveness. From this cross sectional study, 410 patients (female: 61%, male: 39%) were included. The mean age was 81 years (sd: 7.65). The patients suffered from change in verbal behavior (80%), verbal aggressiveness (71%), physical agitation (60%), wandering (48%), and/or physical aggressiveness (31%). The average of disruptive behavior symptoms per patient was 2.9. The symptoms appeared progressively in 81% of patients, the mean duration was two years and it was the first episode in 40% of patients. Disruptive behaviors may be explained in view of organic illness in 62% of patients (cardiovascular disease: 37%, neurologic: 12%, diabetes: 7%, dehydratation: 5%), dementia (Alzheimer disease: 20%, vascular dementia: 18%, mixed dementia: 14%). In 54% of patients disruptive behavior may be explained in view of depression: 34%, and anxiety disorder: 31%. A triggering factor was observed in 57% of cases (psychosocial stress: 39%). Somatic consequences of the symptoms were frequently identified: decrease of alimentary intake: 39%, weight loss: 27%, dehydratation: 11%, falls: 32%, and irregular medication intake: 31%. Limitation of daily life activities: 85%, and family life: 97% were also noted. Acceptability of patient's symptoms by the family was good (no discomfort or transitory and mild irritability) in 61% of cases, and very bad (reactions of exhaustion, hospitalization requirement) in 13%. This study carried out during primary care, showed that the elderly's disruptive behaviors cause severe medical consequences and familial and social distress.

Synthesis of multiply substituted, ion channel forming octi(p-phenylene)s: theme and variations

[reaction: see text] To facilitate the access to unique models for biological processes, we examined six different synthetic routes to octi(p-phenylene) rods with lateral and terminal substituents R(L) and R(T). This systematic study allowed us to increase to overall yield for the synthesis of a new class of oligo(p-phenylene) ionophores about 20 times and to provide general insights into the practicability of synthetic routes to multiply substituted molecular rods.

[Value of tiapride for agitation in the elderly. Review of published studies]

Among elderly disruptive behavior agitation and aggressiveness are frequent and often related to dementia. They are known for increasing the risk of patients' institutionalization and causing distress to families and care givers. When a drug prescription is required, physicians have to take into account the high sensitivity of elderly. Tiapride is an atypical neuroleptic which acts preferentially on D2 and D3 dopaminergic receptors. Several papers concerning results of clinical trials conducted in Europe and Japan have been published and reviewed in this article. The interest of tiapride in the treatment of elderly agitation and aggressiveness has been assessed in four double blind clinical trials including more than 700 patients. The efficacy of tiapride (aggressiveness, agitation, delusion and wandering) was demonstrated in a trial versus placebo (p = 0.027) including 324 patients treated for 28 days with 75 to 150 mg/d. Furthermore the superiority of tiapride (175 to 450 mg/d) on chlorpromazine (18 to 112.5 mg/d) was shown in two trials where 262 patients were treated for four weeks, and a recent survey highlighted that tiapride (400 mg/d) is as efficient as melperone (100 mg/d), the only neuroleptic to be indicated in treatment of elderly agitation and aggressiveness in Germany. Besides, 30 open clinical trials including around 1,000 patients have been conducted and have shown homogeneous and positive results. In the two trials versus chlorpromazine, the safety of tiapride was better, with especially less drowsiness, extrapyramidal symptoms, and dry mouth. Compared to lorazepam, in healthy subjects, tiapride caused less memory impairment. European and Japanese open studies confirmed the safety of tiapride in the elderly. In conclusion, tiapride at doses of 100 to 300 mg/d, appeared to be a therapy of elderly agitation and aggressiveness, at less as efficient as the other drugs used in this indication. Furthermore, the safety of tiapride is an advantage compared to benzodiazepines and neuroleptics.

[Evaluation of efficacy and tolerance of amisulpride in treatment of schizophrenic psychoses]

Amisulpride is a benzamide derivative atypical antipsychotic characterized by selective blockade of dopamine D3 and D2 receptors, limbic selectivity and preferential blockade of dopamine autoreceptors at low doses. Its efficacy on predominant negative symptoms of schizophrenia at low doses, and on the positive symptoms at doses from 400 to 1,200 mg/day has been demonstrated in several controlled studies. The aim of our study was to assess the use in psychiatric clinical practice under naturalistic conditions, efficacy and safety of amisulpride and patient's ability to cope with social skills during a 3-month period of treatment with a follow-up at 6 months. A total of 445 patients (293 men and 152 women), between 18 and 45 years of age, were included in the study DSM III-R criteria of schizophrenia, paranoid type (295.3), or schizophreniform disorder (295.4) were required for inclusion. The patients received amisulpride with flexible dosage between 600 and 1,200 mg/d during a 3-month period (792 mg/d +/- 318). Evaluation was based on the Brief Psychiatric Rating Scale (BPRS), on the Positive And Negative Symptoms Scale (PANSS), and on Clinical Global Improvement scale, completed at D0, D14, D28, D60 and D90. Safety was also assessed with a comprehensive statement of adverse events and with the Simpson-Angus scale of extra pyramidal symptoms. A scale of social adaptation (Echelle d'Adaptation PsychoSociale) was completed at D0, D90 and D180. During the 3-month period of treatment, 124 patients (27.9%) dropped out the trial, including 24 cases of inefficacy and 27 cases of concomitant events. Intent-to-treat analysis showed a significant improvement of BPRS scores (40.2 vs 67.6; p < 0.0001), of positive PANSS scores (13.9 vs 27.7; p < 0.0001), and negative PANSS scores (17.45 vs 28.3; p < 0.0001) between D0 and D90. CGI results confirmed these figures. Follow-up assessment at D180 showed a sustained response on BPRS ans PANSS scores. Amisulpride was well tolerated in the study, with 21% of patients reporting adverse events, in majority psychiatric or endocrine disturbances. Only seven adverse events were assessed as serious. Extra pyramidal symptoms remained low during the study, as measured with Simpson-Angus scale. The EAPS scale showed a significant improvement of social adaptation during the treatment, with a sustained response during the 3-month follow-up period. In conclusion, 600-1 200 mg/d of amisulpride is an effective and well tolerated treatment of schizophrenic disorders, as demonstrated through this 3-month study carried in a large sample of 445 patients. Besides results suggest that under treatment with amisulpride in schizophrenic patients patients' ability to social adaptation can be improved, which could facilitate their rehabilitation.

A comparison of the fluorescence properties of TMA-DPH as a probe for plasma membrane and for endocytic membrane

In earlier studies, the fluorescence probe 1-(4-(trimethylamino)phenyl)-6-phenylhexa-1,3,5-triene (TMA-DPH) was shown to interact with living cells by instantaneous incorporation into the plasma membrane, according to a water (probe not fluorescent)/membrane (probe highly fluorescent) partition equilibrium. This made it interesting both as a fluorescence anisotropy probe for plasma membrane fluidity determinations and as a quantitative tracer for endocytosis and intracellular membrane traffic. In order to ascertain the limiting concentrations for its use in these applications, we performed a systematic study of its fluorescence properties (intensity, lifetime, anisotropy) in the plasma membrane and in endocytic membranes of intact L929 mouse fibroblasts. Some of the experiments were repeated on mouse-bone-marrow-derived macrophages and on phospholipidic LUV to confirm the results. Rather unexpectedly, it was observed that: (i) the incorporation of TMA-DPH into the membranes, monitored by UV absorption measurements, remained proportional to the probe concentration over the wide range explored (5 x 10(-7) M-2.5 x 10(-5) M); (ii) however, concerning fluorescence, quenching effects occurred in the membranes above certain critical concentrations. These effects were shown to result from Förster-type resonance auto-transfer; (iii) strikingly, the critical concentrations were considerably higher in early-endocytic-vesicle membranes than in the bulk plasma membrane. It was established that membrane fluidity was involved and this was confirmed by the parallel study on phospholipidic vesicles. Potential applications of these properties as a novel approach for evaluating membrane fluidity are suggested.

Decreased muscle glucose transport/phosphorylation is an early defect in the pathogenesis of non-insulin-dependent diabetes mellitus

Recent studies have demonstrated that reduced insulin-stimulated muscle glycogen synthesis is the major cause of insulin resistance in patients with non-insulin-dependent diabetes mellitus (NIDDM). This reduced rate has been assigned to a defect in either glucose transport or hexokinase activity. However it is unknown whether this is a primary or acquired defect in the pathogenesis of NIDDM. To examine this question, we measured the rate of muscle glycogen synthesis and the muscle glucose 6-phosphate (G6P) concentration using 13C and 31P NMR spectroscopy as well as oxidative and nonoxidative glucose metabolism in six lean, normoglycemic offspring of parents with NIDDM and seven age/weight-matched control subjects under hyperglycemic (approximately 11 mM)-hyperinsulinemic (approximately 480 pM) clamp conditions. The offspring of parents with NIDDM had a 50% reduction in total glucose metabolism, primarily due to a decrease in the nonoxidative component. The rate of muscle glycogen synthesis was reduced by 70% (P < 0.005) and muscle G6P concentration was reduced by 40% (P < 0.003), which suggests impaired muscle glucose transport/hexokinase activity. These changes were similar to those previously observed in subjects with fully developed NIDDM. When the control subjects were studied at similar insulin levels (approximately 440 pM) but euglycemic plasma glucose concentration (approximately 5 mM), both the rate of glycogen synthesis and the G6P concentration were reduced to values similar to the offspring of parents with NIDDM. We conclude that insulin-resistant offspring of parents with NIDDM have reduced nonoxidative glucose metabolism and muscle glycogen synthesis secondary to a defect in muscle glucose transport/hexokinase activity prior to the onset of overt hyperglycemia. The presence of this defect in these subjects suggests that it may be the primary factor in the pathogenesis of NIDDM.

Determinants of coenzyme specificity in glyceraldehyde-3-phosphate dehydrogenase: role of the acidic residue in the fingerprint region of the nucleotide binding fold

On the basis of the three-dimensional structure of the glycolytic NAD-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and of sequence comparison with the photosynthetic NAD(P)-dependent GAPDH of the chloroplast, a series of mutants of GAPDH from Bacillus stearothermophilus have been constructed. The results deduced from kinetic and binding studies suggest that the absence of activity of the wild-type GAPDH with NADP as a cofactor is the consequence of at least three factors: (1) steric hindrance, (2) electrostatic repulsion between the charged carboxyl group of Asp32 and the 2'PO4, and (3) structural determinants at the subunit interface of the tetramer. The best value for kcat/KM and KD for NADP was observed for the D32A-L187A-P188S mutant. This triple mutation leads to a switch in favor of NADP specificity but with a kcat/KM ratio 50- and 80-fold less than that observed for the wild type with NAD and for the chloroplast GAPDH with NADP, respectively. Substituting the invariant chloroplastic Thr33-Gly34-Gly35 for the B. stearothermophilus Leu33-Thr34-Asp35 residues on the double mutant Ala187-Ser188 does not improve significantly the affinity for NADP while substituting Ala32 for Asp32 on the double mutant does. Clearly, other subtle adjustments in the adenosine subsite are needed to reconcile the presence of the carboxylate group of Asp32 and the 2'-phosphate of NADP. Kinetic studies indicate a change of the rate-limiting step for the mutants. This could be the consequence of an incomplete apo-holo transition.(ABSTRACT TRUNCATED AT 250 WORDS)

Ca(2+)- and Mg(2+)-dependent binding of annexin II and its complex to phospholipid vesicles; a comparative spectroscopic study

The binding of annexin II (p36) and of its complex ((p36)2 (p11)2) to model phospholipid vesicles led to conformational changes of the proteins which were studied by fluorescence spectroscopy. Titrations with liposomes of different kinds showed that the presence of the p11 dimer in the complex enhances the conformational change of the annexin II. Comparative liposome titrations were carried out in the presence of Mg2+: the binding of the protein to liposome induced a much smaller protein conformational change in this case. Moreover, Ca2+ and phospholipid binding order experiments showed that the protein conformational change only occurred when both are bound.

Spondylometaphyseal dysplasia, Sedaghatian type

In 1980 Sedaghatian described an Iranian infant who died shortly after birth. At autopsy, he was found to have subacute myocarditis, cortical necrosis of kidneys, and adrenal and pulmonary hemorrhage. His skeletal abnormalities included mild rhizomelic shortness of his limbs and platyspondylyl and "laciness" of the iliac wings. In 1987 Optiz et al. described another Iranian infant with a similar perinatal course and roentgenograms. This infant was born to first cousins, suggesting an autosomal recessive single gene defect. We report our findings of another infant with a lethal course.

Heparin-induced conformational change and activation of mucus proteinase inhibitor

Low molecular mass heparin (5.1 kDa) forms a tight complex with mucus proteinase inhibitor, the physiologic neutrophil elastase inhibitor of the upper respiratory tract. This binding strongly enhances the intrinsic fluorescence of the inhibitor and the rate of neutrophil elastase inhibitor association. One mole of this heparin fragment binds 1 mol of inhibitor with a Kd of 50 nM. From the variation of Kd with ionic strength, it is inferred that (i) 85% of the heparin--inhibitor binding energy i due to electrostatic interactions, (ii) about seven ionic interactions are involved in heparin--inhibitor binding. strength, it is inferred that (i) 85% of the heparin--inhibitor binding energy is due to electrostatic interactions, (ii) about seven ionic interactions are involved in heparin--inhibitor binding. and (iii), about one-third of low quantum yield of Trp30, the single tryptophan residue of the inhibitor, blue-shifts its maximum emission wavelength by 6 nm, decreases the acrylamide quenching rate constant by a factor of 4, and increases the mean intensity weighted lifetime by a factor of 2.5. These important spectroscopic changes evidence a heparin--induced conformational change of the inhibitor which buries Trp30 in a very hydrophobic environment. Heparin accelerates the inhibition of elastase in a concentration-dependent manner. When both enzyme and inhibitor are saturated by the polymer, the second-order association rate constant is 7.7 x 10(7) M-1 s-1, a value that is 27-fold higher than that measured with the free partners. This finding may have important physiologic and therapeutic bearing.

Solid phase synthesis of the retroviral nucleocapsid protein NCp10 of Moloney murine leukaemia virus and related "zinc-fingers" in free SH forms. Influence of zinc chelation on structural and biochemical properties

The core of retroviruses contains a highly conserved, low molecular weight, basic protein that binds nucleic acids and is essential for genomic RNA packaging. The 56 amino acid protein, NCp10, of Moloney Murine Leukaemia virus (MoMuLV) has the CysX2 CysX4 HisX4 Cys zinc finger-like motif shared by all retrovirus nucleocapsid proteins. The native protein and five modified peptides containing the zinc binding domain were synthesized by solid phase in order to investigate the structural and biochemical role of Zn2+ chelation in MoMuLV NCp10 activity. The purity of the synthetic molecules was verified by HPLC and their sequences were confirmed by amino acid analysis and sequencing in the case of NCp10. Thiol dosage agreed with the theoretical value of free cysteine for all these molecules. Fluorescence measurements performed on synthetic NCp10 and zinc finger fragments showed that the tryptophan quantum yield was Zn2(+)-dependent, allowing a 1:1 stoichiometry for the complex to be determined. The apparent affinity constant of NCp10 for the metal was estimated to be superior to 10(6) M-1. The synthetic protein, in the presence of Zn2+ ions, possesses all the biological properties of NCp10 isolated from virions. It catalyzes both the MoMuLV RNA dimerization and the annealing of the replication primer tRNA(Pro) onto MoMuLV RNA.

The nicotinamide subsite of glyceraldehyde-3-phosphate dehydrogenase studied by site-directed mutagenesis

Directed mutagenesis has been used to study the nicotinamide subsite of the glycolytic NAD-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Residue Asn313 is involved together with the carboxyamide moiety of the nicotinamide ring in a complex network of hydrogen bonding interactions which fix the position of the pyridinium ring of NAD to which hydride transfer occurs at the C-4 position in the catalytic reaction. The asparagine side-chain has been replaced by that of the Thr and Ala residues and results in mutants with very similar properties. Both mutants show much weaker binding of NAD and lower catalytic efficiency. The mutant Asn313----Thr still exhibits strict B-stereospecificity in hydride transfer and retains the property of negative co-operativity in NAD binding. These experiments strongly suggest that the mutant enzyme undergoes the apo----holo sub-unit structural transition associated with coenzyme binding but that the nicotinamide ring is no longer as rigidly held in its pocket as in the wild type enzyme. The results shed light on the details of the molecular interactions which are responsible for negative co-operativity in this enzyme.

Structural and ion-binding properties of an S100b protein mixed disulfide: comparison with the reappraised native S100b protein properties

S100b protein, chemically modified by thioethanol groups (linked via disulfide bonds to two out of four Cys per dimer) was largely similar to reduced native S100b protein in its overall structure and differed only by small modifications extending, however, to the whole protein structure. Studies combining direct Ca2+ binding and associated conformational changes revealed that this chemical modification markedly increased the Ca2(+)-binding affinities (especially in the presence of physiological concentrations of K+ and Mg2+) and introduced a strong positive cooperativity. Different binding models are discussed and it emerges that in both proteins the Ca2(+)-binding sites are not equivalent and probably interact. Like the reduced protein, chemically modified S100b protein binds four Zn2+ ions in two classes of sites (of high and low affinities). Whereas the overall Zn2+ affinity was only slightly decreased, the binding sequence was probably reversed by the introduction of thioethanol groups. Moreover, in the presence of zinc, the Ca2+ affinities were higher and even identical, in both proteins.

Involvement of cytoplasmic membranes in the non-lytic infection of K-562 cells by Semliki Forest virus

An analysis of the human leukemia cell line, K-562, infected with Semliki Forest virus, has been made with transmission electron microscopy. In contrast to the usual surface budding of the enveloped virus on the plasma membrane of vertebrate cells leading to cytolysis within 20 h, K-562 cells do not show surface budding, and the cells remain intact for periods of several months. Several unusual features of the infection include: 1) the rough endoplasmic reticulum arranges early into continuous perinuclear chains; 2) during the time of virus replication and release, the nucleocapsids aggregate on the cytoplasmic side of internal vesicles in the region of the cell where the Golgi complex is normally located; and 3) during this same time period, the vesicles are seen to contain enveloped virions and rod-like formations, a result suggesting that budding has occurred into these vesicles. Viruses are presumably released from the cell as these vesicles fuse with the plasma membrane. By 12 days post-infection and thereafter, the intact cells show electron-dense aggregates of chromatin, large vacuoles and lipid inclusions throughout the cytoplasm, and only a few virion-containing vesicles.

Spectroscopic evidence of two melittin molecules bound to Ca2+-calmodulin

According to Comte et al. (Comte, M., Maulet, Y. and Cox, J.A., (1983), Biochem.J., 209, 269-272), melittin (Mel) gives rise to a one:one complex. We evidence here, by fluorescence anisotropy and gel filtration binding assay (in the presence of 5 mM CaCl2 and 100 mM NaCl) the existence of two complexes: the well-known CaM.Ca4.Mel and a second CaM.Ca4.Mel2 which had not yet been reported. The affinity of Mel for the CaM.Ca4.Mel species is about three orders of magnitude lower than the affinity of Mel for the CaM-Ca4 species.

Comparative effects of calmodulin inhibitors on calmodulin's hydrophobic sites and on the activation of cyclic nucleotide phosphodiesterase by calmodulin

Experiments were designed to investigate the effect of inhibitors on calmodulin's hydrophobic sites and their consequences on the activation of a target enzyme, cyclic nucleotide phosphodiesterase. Two fluorescent probes, 2-(p-toluidinyl)-naphthalene-6-sulfonate (TNS) and 9-anthroylcholine (9AC) were used to study the interactions with calmodulin of inhibitors devoid of direct effect on the probes. Contrary to W-7, nicergoline, nicardipine and quercetin, which decreased the fluorescence of the two probes bound to calmodulin, bepridil only decreased 9AC fluorescence but increased the fluorescence intensity at the wavelength of the emission maximum of TNS. In spite of this difference, bepridil as well as W-7 and nicergoline competitively inhibited calmodulin activation of phosphodiesterase. In addition, nicergoline also inhibited phosphodiesterase activity competitively to cyclic GMP. These results show differences in the interactions of inhibitors with calmodulin; these differences are not detected in functional studies of the effect of inhibitors on phosphodiesterase activation.

Ions binding to S100 proteins. I. Calcium- and zinc-binding properties of bovine brain S100 alpha alpha, S100a (alpha beta), and S100b (beta beta) protein: Zn2+ regulates Ca2+ binding on S100b protein

Flow dialysis measurements of calcium binding to bovine brain S100 alpha alpha, S100a (alpha beta), and S100b (beta beta) proteins in 20 mM Tris-HCl buffer at pH 7.5 and 8.3 revealed that S100 proteins bind specifically 4 Ca2+ eq/mol of protein dimer. The specific calcium-binding sites had, therefore, been assigned to typical amino acid sequences on the alpha and beta subunit. The protein affinity for calcium is much lower in the presence of magnesium and potassium. Potassium strongly antagonizes calcium binding on two calcium-binding sites responsible for most of the Ca2+-induced conformational changes on S100 proteins (probably site II alpha and site II beta). Zinc-binding studies in the absence of divalent cations revealed eight zinc-binding sites/mol of S100b protein dimer that we assumed to correspond to 4 zinc-binding sites/beta subunit. Zinc binding to S100b studied with UV spectroscopy methods showed that the occupation of the four higher affinity sites and the four lower affinity sites on the protein dimer were responsible for different conformational changes in S100b structure. Zinc binding on the higher affinity sites regulates calcium binding to S100b by increasing the protein affinity for calcium and decreasing the antagonistic effect of potassium on calcium binding. Zinc-binding studies on S100a and S100 alpha alpha protein showed that the Trp-containing S100 proteins bind zinc more weakly than S100b protein. Calcium-binding studies on zinc-bound S100a proved that calcium- and zinc-binding sites were distinct although there was no increase in zinc-bound S100a affinity for calcium, as in S100b protein. Finally we provide evidence that discrepancies between previously published results on the optical properties of S100b protein probably result from oxidation of the sulfhydryl groups in the protein.

Ions binding to S100 proteins. II. Conformational studies and calcium-induced conformational changes in S100 alpha alpha protein: the effect of acidic pH and calcium incubation on subunit exchange in S100a (alpha beta) protein

A rapid separation method for bovine brain S100 alpha alpha, S100a, and S100b protein using fast protein liquid chromatography on a Mono Q column and its application in preparation of a large amount of S100 alpha alpha protein are described. The conformation of S100 alpha alpha in the metal-free forms as well as in the presence of calcium were studied by UV absorption, circular dichroism, intrinsic fluorescence, sulfhydryl reactivity, and interaction with a hydrophobic fluorescent probe. The alpha-subunit appears to have nearly identical conformation in S100 alpha alpha and S100a protein dimers. We also confirmed that only the alpha-subunit exposes hydrophobic domains to solvent in the presence of calcium and that cysteine residues exposed upon Ca2+ binding to S100 proteins correspond to Cys 85 alpha and Cys 84 beta. Incubation of S100a with calcium and KCl proved that calcium binding to the putative calcium-binding sites (site I alpha, I beta) triggers a time- and temperature-dependent conformational change in the protein structure which decreases the antagonistic effect of KCl on calcium binding to sites II alpha and II beta and provokes subunit exchanges between protein dimers and the emergence of S100 alpha alpha and S100b (beta beta) proteins. Dynamic fluorescence measurements showed that incubating calcium at high S100a protein concentrations (greater than 10(-5) M) induces an apparent slow dimer-monomer equilibrium which might result in total subunit dissociation at lower protein concentrations. The effect of acidic pH on subunit dissociation in S100a protein (Morero, R. D., and Weber, G. (1982) Biochim. Biophys. Acta 703, 231-240) arises from conformational changes in the protein structure that are similar to those induced by Ca2+ incubation.

Purification, calcium-binding properties, and conformational studies on a 28-kDa cholecalcin-like protein from bovine brain

A large-scale preparation method for bovine brain 28-kDa cholecalcin-like protein is described. Flow dialysis binding studies revealed that the protein binds at least 3 mol of Ca2+/mol of protein. The protein undergoes conformational changes on binding calcium as shown by UV differential absorption spectroscopy, near and far UV circular dichroism, and intrinsic fluorescence. Circular dichroism (CD) studies in the far UV indicate an apparent increase in helical content in the presence of Ca2+. The effect of calcium on the protein structure is nearly maximum for 1 Ca2+ bound/protein molecule. UV differential absorption studies on the binding of the Ca2+ agonist Tb3+ and Tb3+ luminescence induced by energy Trp----Tb3+ transfer indicate that Tb3+ binds to two higher affinity Ca2+-binding sites. These sites are probably very close to the single Trp residue. Analysis of the fluorescence parameters of the single tryptophan residue in the apoprotein and its accessibility to ionic and neutral quenchers suggests that this residue is located in a highly hydrophobic domain on the protein surface.

Rat brain S100b protein: purification, characterization, and ion binding properties. A comparison with bovine S100b protein

We purified to homogeneity rat brain S100b protein, which constitutes about 90% of the soluble S100 protein fraction. Purified rat S100b protein comigrates with bovine S100b protein in nondenaturant system electrophoresis but differs in its amino acid composition and in its electrophoretic mobility in urea-sodium dodecyl sulfate-polyacrylamide gel with bovine S100b protein. The properties of the Ca2+ and Zn2+ binding sites on rat S100b protein were investigated by flow dialysis and by fluorometric titration, and the conformation of rat S100b in its metal-free form as well as in the presence of Ca2+ or Zn2+ was studied. The results were compared with those obtained for the bovine S100b protein. In the absence of KCl, rat brain S100b protein is characterized by two high-affinity Ca2+ binding sites with a KD of 2 X 10(-5) M and four lower affinity sites with KD about 10(-4) M. The calcium binding properties of rat S100b protein differ from bovine S100b only by the number of low-affinity calcium binding sites whereas similar Ca2+-induced conformational changes were observed for both proteins. In the presence of 120 mM KCl rat brain S100b protein bound two Zn2+-ions/mol of protein with a KD of 10(-7) M and four other with lower affinity (KD approximately equal to 10(-6) M). The occupancy of the two high-affinity Zn2+ binding sites was responsible for most of the Zn2+-induced conformational changes in the rat S100b protein. No increase in the tyrosine fluorescence quantum yield after Zn2+ binding to rat S100b was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Purification, characterization and ion binding properties of human brain S100b protein

Human brain S100b (beta beta) protein was purified using zinc-dependent affinity chromatography on phenyl-Sepharose. The calcium- and zinc-binding properties of the protein were studied by flow dialysis technique and the protein conformation both in the metal-free form and in the presence of Ca2+ or Zn2+ was investigated with ultraviolet spectroscopy, sulfhydryl reactivity and interaction with a hydrophobic fluorescence probe 6-(p-toluidino)naphthalene-2-sulfonic acid (TNS). Flow dialysis measurements of Ca2+ binding to human brain S100b (beta beta) protein revealed six Ca2+-binding sites which we assumed to represent three for each beta monomer, characterized by the macroscopic association constants K1 = 0.44 X 10(5) M-1; K2 = 0.1 X 10(5) M-1 and K3 = 0.08 X 10(5) M-1. In the presence of 120 mM KCl, the affinity of the protein for calcium is drastically reduced. Zinc-binding studies on human S100b protein showed that the protein bound two zinc ions per beta monomer, with macroscopic constants K1 = 4.47 X 10(7) M-1 and K2 = 0.1 X 10(7) M-1. Most of the Zn2+-induced conformational changes occurred after the binding of two zinc ions per mole of S100b protein. These results differ significantly from those for bovine protein and cast doubt on the conservation of the S100 structure during evolution. When calcium binding was studied in the presence of zinc, we noted an increase in the affinity of the protein for calcium, K1 = 4.4 X 10(5) M-1; K2 = 0.57 X 10(5) M-1; K3 = 0.023 X 10(5) M-1. These results indicated that the Ca2+- and Zn2+-binding sites on S100b protein are different and suggest that Zn2+ may regulate Ca2+ binding by increasing the affinity of the protein for calcium.

Intrinsic fluorescence of a non-myelin apoproteolipid and evidence for the existence of conformational flexibility

An extremely hydrophobic protein (Mr = 16000), which in its native form is only soluble in organic solvents and which differs from the myelin proteolipid (Mr = 24000), was purified to homogeneity. Intrinsic fluorescence studies on this apoproteolipid have revealed a large conformational flexibility. In the water-soluble form the emitting residues appear to be buried in a hydrophobic core while in organic solvents they are exposed to the external medium. Structural changes depending on the organic solvent are also observed. The emission characteristics of reconstituted proteoliposomes may be due to the formation of a membrane-linked complex between several proteolipid monomers.

Fluorescence investigations of calmodulin hydrophobic sites

Calmodulin activation of target enzymes depends on the interaction between calmodulin hydrophobic regions and some enzyme areas. The Ca2+ induced exposure of calmodulin hydrophobic sites was studied by means of 2-p-toluidinylnaphthalene-6-sulfonate, a fluorescent probe. Scatchard and Job plots showed that the calmodulin-Ca42+ complex bound two molecules of this hydrophobic probe, with KD congruent to 1.4 X 10(-4) M. These sites are not totally exposed until calmodulin has bound four Ca2+ per molecule, so the conformational change is not over before the four specific Ca2+ - binding sites are saturated with Ca2+.

The effect of S-100a and S-100b proteins and Zn2+ on the assembly of brain microtubule proteins in vitro

The homologous proteins S-100a and S-100b affect the microtubule system in a distinctly different way in the presence of low molar ratios of Zn2+. Assembly of brain microtubule proteins can be almost completely inhibited and rapid disassembly can be induced by low molar amounts of S-100b in the presence of low molar ratios [2-4] of Zn2+. Higher molar ratios per S-100b (greater than 4) potentiate the general Zn2+ effect, promoting the formation of sheets of microtubules. However, the effect of S-100a is quite different, no inhibition of assembly can be observed and the presence of S-100a seems to protect the microtubule proteins against the effect of Zn2+ by chelating the Zn2+ and decreasing the free metal-ion concentration. S-100a or S-100b cannot bind to the microtubule polymer-form, either in the absence or in the presence of Zn2+.