Characterization of the thyrotropin binding pocket.

A panel of monoclonal antibodies (mAbs) to the thyrotropin receptor (TSHR) was prepared using three different immunization strategies. The mAbs obtained (n = 138) reacted with linear epitopes covering most of the TSHR extracellular domain and with conformational epitopes. mAbs that bound to five different regions of the TSHR (amino acids [aa] 32-41, aa 36-42, aa 246-260, aa 277-296, and aa 381-385) were able to inhibit (125)I-labeled thyrotropin (TSH) binding to solubilized TSHR preparations. Fab and immunoglobulin G (IgG) preparations were similarly effective inhibitors for mAbs reactive with aa 246-260, aa 277-291 and aa 381-385 suggesting that these three regions of the TSHR are involved in TSH binding. In contrast mAbs reactive with aa 32-41 and aa 36-42 were not effective at inhibiting TSH binding when Fab preparations were used, suggesting that these N terminal regions of the TSHR were less critical for TSH binding. Our studies suggest that three distinct and discontinuous regions of the TSHR (aa 246-260 and 277-296 on the TSHR A subunit) and aa 381-385 (on the TSHR B subunit) fold together to form a complex TSH binding pocket. Alignment of the aa sequences of these three regions in TSHRs from different species indicates that they are highly conserved.     

Cardiovascular Autonomic Function in Conscious Rats: A Novel Approach to Facilitate Stationary Conditions

Background An experimental setting and software were developed to evaluate cardiovascular autonomic function in conscious rats. A restrained approach was used, which, upon proper habituation, induced little or no stress in the rats and limited motion artifacts. Methods: The ECG and arterial blood pressure were recorded. Time‐ and frequency‐domain indices of heart rate variability (HRV) and blood pressure variability (BPV) were calculated. The spontaneous baroreflex sensitivity (spBRS) was estimated using the method of statistical dependence. Results: The power spectra clearly concentrated in a frequency band with center frequency around 0.4 Hz, the low frequency (LF) component, and one at the respiratory frequency at 1.5 Hz, the high frequency (HF) component. In baseline conditions, a direct association existed between mean R‐R and especially HRV parameters denoting vagal modulation such as rMSSD, pNN5, and HF power. Beta‐adrenergic blockade by propranolol diminished basal heart rate. Vagal indices increased while there was an exclusive decrease in the low frequency band of HRV. Alpha‐adrenergic blockade with phentolamine produced a depressor response with tachycardia, and a clear decrease in the LF component of BPV. Both the LF and HF component in the HRV spectrum were virtually absent. Cholinergic blockade with atropine did not significantly alter BP but induced a clear tachycardia with decreased vagal indices. The HF component of HRV was completely abolished and the LF band was reduced. Conclusions: Both a‐ and 13‐adrenergic blockade left 5pBRS virtually unaltered, while cholinergic blockade profoundly diminished spBRS. Spectral fluctuations of 13‐sympathetic tone were restricted to the LF range of HRV, while the HF respiratory component represented vagal modulation. The a‐sympathetic system played a dominant role in the LF oscillations of BPV. A role of the vagus in the HF oscillations of BPV in the rat is questioned. The baroreflex depended mainly on changes in vagal activity. A.N.E. 2002;7(4):307–318     

Differentiation-associated staining with anti-pimonidazole antibodies in head and neck tumors.

BACKGROUND AND PURPOSE: Hypoxia is a strong negative prognostic factor for all three major treatment modalities for cancer. The bioreductive drug pimonidazole is currently under clinical investigation as a hypoxia marker. In human head and neck tumors, in addition to staining patterns typical of chronic hypoxia, staining was seen specifically around areas of keratinization, raising the question of whether this is hypoxia-related. This could influence quantitative hypoxia estimates using this marker. We investigated here whether the differentiation-related staining was caused by locally high reductive enzyme levels. PATIENTS AND METHODS: The nitrotetrazolium compound NBT was used, which is reduced by nitroreductases to yield a blue color. The assay was validated on three genetically related MDA231 human mammary carcinoma cell lines: wildtype, overexpressing DT-diaphorase (DT1), and overexpressing cytochrome p450 reductase (R4). Increased NBT staining under normoxia was indeed seen for both R4 and DT1 lines. Pimonidazole staining under normoxia was only seen in the R4 line. RESULTS: Frozen tumor sections from 20 patients with head and neck cancer injected with pimonidazole were incubated with NBT. Parallel sections were stained for pimonidazole. Staining patterns were then compared on matched images, and areas of keratinization scored for the presence or absence of pimonidazole and NBT. Pimonidazole staining was seen in 56% of keratinized areas, and of these, 78% showed increased NBT staining, indicating that high reductase levels are not a necessary requirement for differentiation-associated pimonidazole staining. In a second series, frozen sections of tumors from 15 patients not receiving pimonidazole were incubated with NBT and compared with staining after incubation with pimonidazole under both oxic and hypoxic conditions. Pimonidazole staining of some keratinizing areas under oxic conditions was seen. Of these areas, only a proportion (70%) showed increased NBT staining, confirming the lack of correspondence between keratin-associated pimonidazole staining and reductase levels. CONCLUSION: Hypoxia-independent pimonidazole staining can occur in more differentiated head and neck tumors, necessitating caution in hypoxia quantification. These data argue against a causative role for locally high reductase levels in differentiation-associated staining. DT-diaphorase appears to play no role in pimonidazole reduction.     

Faculty mentorship: support for nurse practitioner students and staff within the rural community health setting

As pointed out in the introduction, there are certain practical concepts within our base of nursing knowledge that can only be taught through experience. Many things are easier to teach by example. As we turn back the clock in nursing, we can see how Florence Nightingale, Clara Barton, and Lillian Wald were role models to their nursing peers in their era. They taught nursing by example, by role modeling their clinical expertise. Today, this model is still effective and faculty mentoring of nurse practitioner students and CHNs in a compassionate and collegial leadership results in higher quality of health care for our nation's needy clients and their families. But greater yet are the opportunities for flexible nurse practitioner faculty practice and personal interactions on many levels for nursing faculty who wish to share their expertise. Mentorship by nurse practitioner faculty for nurse practitioner students and CHNs in a rural clinical setting has revealed many positive aspects in providing quality care for rural clients and growth for nurses. Exposure to the rural community health system helps us, as nurses, to identify the many strengths it possesses for innovative rural nursing practice.     

Time of injury affects urinary biomarker predictive values for acute kidney injury in critically ill,non-septic patients

Background

The predictive value of acute kidney injury (AKI) urinary biomarkers may depend on the time interval following tubular injury, thereby explaining in part the heterogeneous performance of these markers that has been reported in the literature. We studied the influence of timing on the predictive values of tubular proteins, measured before the rise of serum creatinine (SCr) in critically ill, non-septic patients.

Methods

Seven hundred adult critically ill patients were prospectively included for urine measurements at four time-points prior to the rise in serum creatinine (T?=?0, -16, -20 and -24 h). Patients with sepsis and or AKI at ICU entry were excluded. The urinary excretion of the proteins, neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1), which are up-regulated in the distal and proximal tubules, respectively, were measured as well as the constitutive cytoplasmatic enzymes, π- and α-glutathione-S-transferase (GST), which are released by the distal and proximal tubules, respectively.

Results

Five hundred and forty-three subjects were eligible for further analyses; however, 49 developed AKI in the first 48 h. Both NGAL (P?=?0.001 at T?=?-24 vs. non-AKI patients) and KIM-1 (P?<?0.0001 at T?=?0 vs. non-AKI patients) concentrations gradually increased until AKI diagnosis, whereas π- and α-GST peaked at T?=?-24 before AKI (P?=?0.006 and P?=?0.002, respectively vs. non-AKI patients) and showed a rapid decline afterwards. The predictive values at T?=?-24 prior to AKI were modest for π- and α-GST, whereas NGAL sufficiently predicted AKI at T?=?-24 and its predictive power improved as the time interval to AKI presentation decreased (area under the receiver operating characteristic curve; AUC?=?0.79, P?<?0.0001). KIM-1 was a good discriminator at T?=?0 only (AUC?=?0.73, P?<?0.0001).

Conclusions

NGAL, KIM-1, pi- and alpha-GST displayed unique and mutually incomparable time dependent characteristics during the development of non-sepsis related AKI. Therefore, the time-relationship between the biomarker measurements and the injurious event influences the individual test results.

     

Genetic underpinnings of sociability in the general population

Levels of sociability are continuously distributed in the general population, and decreased sociability represents an early manifestation of several brain disorders. Here, we investigated the genetic underpinnings of sociability in the population. We performed a genome-wide association study (GWAS) of a sociability score based on four social functioning-related self-report questions from 342,461 adults in the UK Biobank. Subsequently we performed gene-wide and functional follow-up analyses. Robustness analyses were performed in the form of GWAS split-half validation analyses, as well as analyses excluding neuropsychiatric cases. Using genetic correlation analyses as well as polygenic risk score analyses we investigated genetic links of our sociability score to brain disorders and social behavior outcomes. Individuals with autism spectrum disorders, bipolar disorder, depression, and schizophrenia had a lower sociability score. The score was significantly heritable (SNP h² of 6%). We identified 18 independent loci and 56 gene-wide significant genes, including genes like ARNTL, DRD2, and ELAVL2. Many associated variants are thought to have deleterious effects on gene products and our results were robust. The sociability score showed negative genetic correlations with autism spectrum, disorders, depression, schizophrenia, and two sociability-related traits—loneliness and social anxiety—but not with bipolar disorder or Alzheimer’s disease. Polygenic risk scores of our sociability GWAS were associated with social behavior outcomes within individuals with bipolar disorder and with major depressive disorder. Variation in population sociability scores has a genetic component, which is relevant to several psychiatric disorders. Our findings provide clues towards biological pathways underlying sociability.Subject terms: Bipolar disorder, Schizophrenia, Depression, Behavioural genetics, Autism spectrum disorders     

Stroke caregivers' strain: prevalence and determinants in the first six months after stroke

Purpose. Many disabled stroke survivors live at home supported by informal caregivers. Research has revealed that these caregivers are experiencing strain. This study aims to examine the prevalence and differences over time of caregivers' strain in the first 6 months post-stroke and to predict caregiver strain based on patients' and caregivers' characteristics and service input.

Method. Ninety consecutive patients and their caregivers were assessed at 2, 4 and 6 months post-stroke. The Caregiver Strain Index was used to evaluate strain. Patients' motor function, functional ability, health status, emotion and participation and caregivers' gender and relation to the patient and service input after discharge were measured to determine the predictive factors.

Results. Nearly one out of three caregivers experienced strain. No differences were seen between 2, 4 and 6 months post-stroke. Correlation and multiple regression analyses revealed that in predicting strain, the patients' functional and activity level plays an important role in the sub-acute phase while the participation level gets more important over time.

Conclusions. These findings emphasize the importance of maximal physical recovery and optimal reintegration in the community. This is not only essential for the patients themselves but also a pre-requisite to reduce the strain of their caregivers.     

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Abstract

The article is the second of two describing the contingencies that drive and influence the operations of multidisciplinary palliative care teams. The results of analysis reported here are drawn from data gathered in a total of 11 interviews that took place with management teams and multidisciplinary care delivery teams in three palliative care case study organisations in Sydney, Australia, over a period of some 13 months. A model of the management and operation of multidisciplinary palliative care teams is presented to provide a context and to indicate the scope of the research completed so far.