The need for single registration care homes: the RCN vision

This report discusses the provision of care for people living in nursing and residential homes. It presents the RCN's (1997a) proposals for single registration care homes. In the first of two articles, on page 35 in this week's issue, the authors also examine the statutory framework that currently regulates residential and nursing home provision.

The need for single registration care homes. 1: Current provision

As we await the government White Paper on social services, the authors examine; in the first of two articles, the current two-tier service which means that elderly people are often moved unnecessarily between residential and nursing homes when their health needs change. The Royal College of Nursing's proposals for single registration care homes is explained on pages 32 and 33 in this issue. The second article will appear next week.

Reflection and patterns of knowing in nursing

Over the last decade nursing has progressed from a reliance on empirical theory applied to practice to a recognition that experience develops knowledge that can guide the actions of practitioners. Reflection is a means of surfacing experiential knowledge, and students may begin to use reflection as their experience of nursing accumulates. As Carper was a key figure in widening that knowledge accepted as knowing in nursing beyond the empirical, it is both justified and recommended that her work should be incorporated into reflective practice. Johns has integrated Carper's work in his model of guided reflection and this paper briefly examines this combination. The main focus is on two further patterns of knowing: unknowing and sociopolitical knowing. These patterns are examined and the contribution they could make to reflective practice is discussed.

Interaction of chemokine receptor CCR5 with its ligands: multiple domains for HIV-1 gp120 binding and a single domain for chemokine binding

CCR5 is a chemokine receptor expressed by T cells and macrophages, which also functions as the principal coreceptor for macrophage (M)-tropic strains of HIV-1. To understand the molecular basis of the binding of chemokines and HIV-1 to CCR5, we developed a number of mAbs that inhibit the various interactions of CCR5, and mapped the binding sites of these mAbs using a panel of CCR5/CCR2b chimeras. One mAb termed 2D7 completely blocked the binding and chemotaxis of the three natural chemokine ligands of CCR5, RANTES (regulated on activation normal T cell expressed and secreted), macrophage inflammatory protein (MIP)-1alpha, and MIP-1beta, to CCR5 transfectants. This mAb was a genuine antagonist of CCR5, since it failed to stimulate an increase in intracellular calcium concentration in the CCR5 transfectants, but blocked calcium responses elicited by RANTES, MIP-1alpha, or MIP-1beta. This mAb inhibited most of the RANTES and MIP-1alpha chemotactic responses of activated T cells, but not of monocytes, suggesting differential usage of chemokine receptors by these two cell types. The 2D7 binding site mapped to the second extracellular loop of CCR5, whereas a group of mAbs that failed to block chemokine binding all mapped to the NH2-terminal region of CCR5. Efficient inhibition of an M-tropic HIV-1-derived envelope glycoprotein gp120 binding to CCR5 could be achieved with mAbs recognizing either the second extracellular loop or the NH2-terminal region, although the former showed superior inhibition. Additionally, 2D7 efficiently blocked the infectivity of several M-tropic and dual-tropic HIV-1 strains in vitro. These results suggest a complicated pattern of HIV-1 gp120 binding to different regions of CCR5, but a relatively simple pattern for chemokine binding. We conclude that the second extracellular loop of CCR5 is an ideal target site for the development of inhibitors of either chemokine or HIV-1 binding to CCR5.

Fractures after thyroidectomy in men: a population-based cohort study

Bone mass is purportedly reduced by an endogenous or exogenous excess of thyroid hormone or, perhaps, by calcitonin deficiency. Patients who have undergone thyroidectomy could be subject to all of these effects, yet their practical implications in terms of fracture risk are poorly defined. Interpretation is further hampered by the focus on women, where results may be influenced by involutional osteoporosis. Consequently, we assessed the potential for fractures among the 136 Rochester, Minnesota men who underwent thyroidectomy between 1935 and 1979, relative to a group of age-matched control men from the community. With 2194 person-years of follow-up in each group, survival free of any fracture of vertebra, proximal humerus, distal forearm, pelvis, or proximal femur was similar in the two groups (p = 0.23), and the relative risk of any of these fractures for thyroidectomized patients versus their controls was increased only 1.5-fold (95% CI, 0.7-3.2). The difference was entirely accounted for by a statistically significant excess of proximal femur fractures in the men with thyroidectomy. Risk factors for fractures among men with thyroidectomy included greater age at surgery, greater extent of surgery, and the presence of risk factors for secondary osteoporosis. Thus, thyroidectomy, performed mainly for adenoma or goiter, seems to have little overall influence on the risk of age-related fractures in men. However, the association with hip fractures requires further evaluation.

Chemokine receptor usage by human eosinophils. The importance of CCR3 demonstrated using an antagonistic monoclonal antibody

Chemokines bind and signal through G-protein coupled seven transmembrane receptors. Various chemokine receptors are expressed on leukocytes, and these may impart selective homing of leukocyte subsets to sites of inflammation. Human eosinophils express the eotaxin receptor, CCR3, but respond to a variety of CC chemokines apart from eotaxin, including RANTES, monocyte chemotactic protein (MCP)-2, MCP-3, and MCP-4. Here we describe a mAb, 7B11, that is selective for CCR3 and has the properties of a true receptor antagonist. 7B11 blocked binding of various radiolabeled chemokines to either CCR3 transfectants, or eosinophils. Pretreatment of eosinophils with this mAb blocked chemotaxis and calcium flux induced by all CCR3 ligands. In all individuals examined, including allergic and eosinophilic donors, > 95% of the response of eosinophils to eotaxin, RANTES, MCP-2, MCP-3, and MCP-4 was shown to be mediated through CCR3. The IL-8 receptors, particularly CXCR2, were induced on IL-5 primed eosinophils, however these eosinophils responded to CC chemokines in the same manner as unprimed eosinophils. These results demonstrate the importance of CCR3 for eosinophil responses, and the feasibility of completely antagonizing this receptor.

Autosomal dominant primary hyperparathyroidism and jaw tumor syndrome associated with renal hamartomas and cystic kidney disease: linkage to 1q21-q32 and loss of the wild type allele in renal hamartomas

Hereditary hyperparathyroidism-jaw tumor syndrome (HPT-JT) is an autosomal dominant disease (OMIM 145001) that has recently been mapped to chromosomal region 1q21-q32 (HRPT2). Here we report two families with HPT-JT syndrome in which adult renal hamartomas or cystic kidney disease were prominent associated features, possibly representing a new phenotypic variant of the HPT-JT syndrome. In the first family, renal lesions were present in five out of six affected individuals, whereas HPT and JT were seen in four and two cases, respectively. In the second family, JT was found in three of the five affected individuals and two affected members also exhibited polycystic kidney disease. The possibility of the latter cosegregating as a separate autosomal dominant gene can not be ruled out. A sex-dependent penetrance of primary HPT, resulting in predominantly male-affected cases was evident in the two families. Twenty microsatellite markers in the HRPT2 region were typed, in addition to markers in the multiple endocrine neoplasia (MEN) types 1 and 2 regions at 11q13 and 10q11. The disease in these two kindreds was linked to five markers in the 1q21-q32 region (logarithm-of-odds scores: 3.2-4.2), whereas linkage to the MEN1 and MEN2 regions was excluded. Meiotic recombinations detected in affected individuals placed the locus telomeric of D1S215, thus narrowing the HRPT2 region from > 60 to approximately 34 centimorgans. Loss of heterozygosity was studied in seven renal hamartomas from two affected individuals in the first family, as well as in a jaw tumor and a parathyroid tumor from the second family. All renal hamartomas showed loss of heterozygosity at the 1q21-q32 region. The losses invariably involved the wild type allele derived from the unaffected parent, suggesting the inactivation of a tumor suppressor gene in this region.

Non-suppressible parathyroid hormone secretion is related to gland size in uremic secondary hyperparathyroidism

To determine the relative importance of parathyroid gland enlargement and alterations in calcium sensing (set-point changes) in the pathogenesis of uremic secondary hyperparathyroidism (2 degrees HPT), we investigated the relationship between estimates of parathyroid gland size and calcium-mediated parathyroid hormone (PTH) suppression in 19 normocalcemic 2 degrees HPT patients on chronic maintenance hemodialysis. We compared our results to calcium-mediated PTH suppression in 12 normal volunteers, 12 patients with familial benign hypocalciuric hypercalcemia (FBHH), a disorder of abnormal calcium sensing, and 9 subjects with primary hyperparathyroidism (1 degree HPT), which is characterized by both calcium set-point abnormalities and parathyroid gland enlargement. We found that the 2 degrees HPT group displayed a distinctive pattern of calcium-mediated PTH suppression characterized by a failure to normally suppress PTH at supraphysiologic ionized calcium concentrations, similar to 1 degree HPT, but without the rightward shift of the calcium-PTH suppression curve that characterizes calcium sensing abnormalities in FBHH and 1 degree HPT. In the patients with 2 degrees HPT, hypercalcemic suppression resulted in an ending PTH (as a percent of baseline) that was significantly higher (39.8 +/- 4.47%), and a slope of the calcium-PTH suppression curve that was significantly less negative (-4.8 +/- 0.53), compared to respective values of 19.4 +/- 1.81% (P = 0.0009) and -9.0 +/- 1.02 (P = 0.001) in normals and 19.1 +/- 2.49% (P = 0.001) and -9.6 +/- 1.11 (P = 0.0006) in FBHH. Values of ending PTH and slope in 2 degrees HPT patients, however, were similar to those found in 1 degree HPT (49.8 +/- 6.35%, P = 0.21 and -4.5 +/- 0.74, P = 0.72). The ionized calcium concentration required to attain half maximal PTH suppression (EC50) in 2 degrees HPT (1.20 +/- 0.02 mmol/liter) was not significantly different from normals (1.25 +/- 0.01 mmol/liter, P = 0.12) but was significantly less than in 1 degree HPT (1.52 +/- 0.02 mmol/liter, P < 0.0001) and in FBHH (1.44 +/- 0.02 mmol/liter, P < 0.0001). More importantly, we found a significant linear correlation between the natural logarithm of gland size and ending PTH suppression (r = 0.71, P < 0.001) and slope of the calcium-PTH curve (r = 0.67, P = 0.002) in 2 degrees HPT. Thus, calcium non-suppressible PTH secretion in 2 degrees HPT does not represent a simple set-point error, but rather correlates with the degree of parathyroid gland enlargement.

Developing outcome indicators in continuing care: part 2

In their follow-up to last week's article which described the development of outcome indicators for nursing older people in continuing care settings, the authors describe in detail the process of indicator development. Referring to theoretical models, they provide a practical example of how a nurse could use one of his or her experiences from nursing to illustrate the distinct value of patient interventions provided by a registered practitioner.

Developing outcome indicators in continuing care: part 1

In the first of two articles, the authors describe the development of outcome measures for nursing older people in a continuing care setting. They describe why such a process was initiated and the framework which guided the project, including current nursing and government policy and theories of knowledge and expert practice. The second article will appear next week.

Clustered inactivating mutations and benign polymorphisms of the calcium receptor gene in familial benign hypocalciuric hypercalcemia suggest receptor functional domains

The predominant variety of familial benign hypocalciuric hypercalcemia (FBHH) is FBHH(3q), which is associated with presumed inactivating mutations of the cell surface calcium receptor (CaR) gene on chromosome 3q13.3-q21. We sought mutations of the CaR gene in FBHH by direct sequencing of PCR-amplified genomic DNA from 14 affected families: 8 mapped to 3q13, 1 mapped to chromosome 19p, and 5 unmapped. We sequenced the entire coding region of the gene (exons 2-7) in one or two affected members of each family and found six point mutations that altered one amino acid, cosegregated with hypercalcemia, and were absent in more than 100 unaffected persons. Four mutations were unique (S53P, D215G, S657Y, and P748R), and two had been reported previously (P55L and R185Q). Of four mutant CaR proteins expressed in Xenopus oocytes, three were deficient in extracellular Ca2+-induced signaling. No CaR mutations were found in eight families, including the one mapped to chromosome 19p. Three benign polymorphisms occurred in the COOH-terminal region of the CaR protein in 10%, 15%, and 30% of more than 100 unaffected persons. Thus, FBHH-causing CaR mutations were clustered in the NH2-terminal extracellular and membrane-spanning regions of the receptor protein. We suggest that these are important functional domains, probably for calcium binding and signal transduction, respectively. Finally, mutations in regulatory or intronic regions of the CaR gene may also underlie many cases of FBHH.

Genetic abnormalities in sporadic parathyroid adenomas: loss of heterozygosity for chromosome 3q markers flanking the calcium receptor locus

Inactivating mutations of the parathyroid cell calcium receptor (CaR) gene cause one form of familial benign/hypocalciuric hypercalcemia, and in homozygous form, cause neonatal severe primary hyperparathyroidism with parathyroid hyperplasia. Thus, we postulated that partial or total loss of CaR function might contribute to calcium insensitivity or even stimulate cell proliferation in sporadic parathyroid adenomas (PAds). To examine this possibility, we sought loss of heterozygosity (LOH) for markers flanking the CaR locus (3cen-3q21) in 35 PAds. We used 16 highly-polymorphic PCR-based markers in paired normal and tumor DNA, extracted from slices of archived surgical specimens. Nineteen to 24 of the DNA pairs were informative with at least one marker. In two informative pairs, we found LOH for markers D3S1303, D3S1267, or D3S1269, which are tightly-linked with and flank the CaR locus. In one tumor, deletion mapping confined the lost area between D3S1271 and D3S1238 (41.7 centimorgans, cM). In the other tumor, LOH spanned most of chromosome 3, ranging at least from D3S1307 to D3S1311 (271.4 cM). LOH was confirmed by repetition of the experiments and quantified by phosphorimaging. Thus, we found LOH encompassing the CaR locus in approximately 10% of sporadic PAds. These data are consistent with the hypothesis that loss of CaR function may occur in PAds, with functional consequences for calcium sensitivity and cell proliferation.