Identification of a calcitonin-like diuretic hormone that functions as an intrinsic modulator of the American lobster, Homarus americanus, cardiac neuromuscular system.

In insects, a family of peptides with sequence homology to the vertebrate calcitonins has been implicated in the control of diuresis, a process that includes mixing of the hemolymph. Here, we show that a member of the insect calcitonin-like diuretic hormone (CLDH) family is present in the American lobster, Homarus americanus, serving, at least in part, as a powerful modulator of cardiac output. Specifically, during an ongoing EST project, a transcript encoding a putative H. americanus CLDH precursor was identified; a full-length cDNA was subsequently cloned. In silico analyses of the deduced prepro-hormone predicted the mature structure of the encoded CLDH to be GLDLGLGRGFSGSQAAKHLMGLAAANFAGGPamide (Homam-CLDH), which is identical to a known Tribolium castaneum peptide. RT-PCR tissue profiling suggests that Homam-CLDH is broadly distributed within the lobster nervous system, including the cardiac ganglion (CG), which controls the movement of the neurogenic heart. RT-PCR analysis conducted on pacemaker neuron- and motor neuron-specific cDNAs suggests that the motor neurons are the source of the CLDH message in the CG. Perfusion of Homam-CLDH through the isolated lobster heart produced dose-dependent increases in both contraction frequency and amplitude and a dose-dependent decrease in contraction duration, with threshold concentrations for all parameters in the range 10(-11) to 10(-10) mol l(-1) or less, among the lowest for any peptide on this system. This report is the first documentation of a decapod CLDH, the first demonstration of CLDH bioactivity outside the Insecta, and the first detection of an intrinsic neuropeptide transcript in the crustacean CG.

What attributes determine quality and satisfaction with health care delivery?

Patient-based determinants of quality and satisfaction play an important role in choosing a health care provider. This study identifies five attributes of health care delivery that define patients' perceptions of quality and satisfaction. Managerial implications for diagnosing quality concerns of patients are discussed.

Influencing physician referrals.

Primary care physicians have several external sources of information available when referring a patient to a specialist. The most-used sources were a fellow physician, followed by the specialist, the patient or the patient's family, and to a lesser extent, hospital-controlled sources including referral directories, call services, and sales representatives. The authors tested a cost-benefit model where source usage was predicted to increase as the costs of using the source decreased and benefits increased.

Challenges and opportunities for personal selling.

Health care organizations are beginning to use sales forces in much the same way as traditional for-profit organizations have used selling programs in the past. However, numerous challenges to the implementation of selling in the health care industry have yet to be overcome. The authors report viewpoints expressed by administrators in a national survey of health care organizations.

Personal selling in health care organizations: a status report.

The authors report the state of the art of personal selling in health care organizations in the United States. The research was conducted through the use of a previously validated sales orientation index, administered to various types of health care organizations. The findings indicate that personal selling is far from being a fully integrated promotional tool in the health care industry. Differences in the sales orientation of health care organizations are found to be related to environmental and organizational factors.

A model of service quality perceptions and health care consumer behavior.

Analysis of covariance structures (LISREL) was used to examine the influence of consumer held perceptions of service quality on consumer satisfaction and intentions to return. Results indicate that service quality is a significant predictor of consumer satisfaction which, in turn, predicts intention to return. Health care marketing implications are discussed.

Product line management in hospitals: an exploratory study of managing change.

Hospitals often have looked to industry as a source of solutions to business problems. In recent years, they have begun to adopt a concept that has been used by manufacturers for more than 50 years--product line management (PLM). One characteristic of PLM is the designation of a product champion whose responsibility it is to promote the product both inside and outside the organization as well as to view for organizational resources to support the product. This article presents the findings of an exploratory study that indicates that although many hospitals are successfully utilizing PLM, a number of barriers to the implementation of this concept remain.

Connective tissue-associated proteins in crevicular fluid: potential markers for periodontal diseases.

Tests for periodontal disease that are able to detect both ongoing and future loss of clinical attachment would be valuable assets in determining the diagnosis and treatment of periodontal diseases. We hypothesized that connective tissue-associated proteins could be detected in crevicular fluid and would reflect the biochemical activity of the periodontium in health and disease. To test this hypothesis, crevicular fluid samples obtained from patients with various states of periodontal disease were analyzed for the presence of several connective tissue-associated proteins using a dot blot assay. Two such proteins, osteonectin and N-propeptide alpha I type I collagen, were detected in crevicular fluid samples of patients with periodontal disease. Furthermore, the amount of these proteins detected in crevicular fluid appeared to increase with increased probing depth at the sampled site. These studies indicate that measurements of connective tissue-associated proteins in crevicular fluid may prove to be a valuable tool for diagnosing periodontal diseases.

Altered bacterial aggregation and adherence associated with changes in rat parotid-gland salivary proteins induced in vivo by beta-adrenergic stimulation.

Reduced adherence and aggregation were associated with protein alterations in parotid saliva after chronic treatment with the beta-adrenergic agonist isoproterenol. In contrast, saliva from animals treated with the beta-antagonist, propranolol, did not cause such changes; the protein composition of this saliva was similar to that of controls. SDS-polyacrylamide gel electrophoresis of protein in saliva samples before and after they were mixed with 10 mg of spheroidal hydroxyapatite beads (HA), as well as protein adsorbed and recovered from the HA, showed that an acidic, proline-rich protein with a molecular weight of approx. 40,000 was the predominant protein adsorbed. This protein was significantly diminished in saliva from isoproterenol-treated rats. Proteins with molecular weights between 44,000 and 48,000 and unique to the saliva from isoproterenol-treated animals were also adsorbed to HA. Thus alterations in proline-rich proteins of parotid saliva may influence the adherence and aggregation of oral bacteria, two processes considered important for in-vivo colonization of oral surfaces.

Secretion of antimicrobial proteins from the parotid glands of different aged healthy persons.

The secretion of three antimicrobial proteins from the parotid glands of 82 generally healthy men and women, 22 to 81 years in age, was examined. No change was observed in the levels of secretory IgA, but statistically significant, modest elevations (approximately 50 to 100%) of lactoferrin, in both unstimulated and stimulated secretions, and lysozyme, in unstimulated secretions, were detected when results were expressed as mg antimicrobial protein/100 ml saliva. However, these alterations were not observed if data were expressed as mg antimicrobial protein/g total protein. Also, no change was detected in an acinar cell exocrine product, the anionic proline-rich proteins, as reported previously by our laboratory. The data are consistent with a maintenance of protective functions in parotid saliva during aging.

Developing new services for hospitals: a suggested model.

Hospitals tend to use an incomplete means of developing new services. The result is a lack of attention to the needs of the intended target markets. A model for developing new hospital services is suggested, one that allows greater input from the service recipients. An illustrative case is presented.

Oral and sialochemical findings in patients with autoimmune rheumatic disease.

Forty-two patients with autoimmune rheumatic diseases were evaluated for oral-dental findings and a biopsy of labial minor salivary glands was obtained. Stimulated parotid salivary gland function was assessed and levels of total protein, chloride and albumin in these secretions measured. The patients were stratified into three groups according to the severity of labial gland histopathology (normal histology, 1+ and 2+). Individuals with chronic inflammatory disease of the minor salivary glands had no decrease in stimulated parotid salivary flow but were found to have a greater incidence of oral soft tissue changes commonly associated with salivary dysfunction. However, there were no statistically significant differences in total protein or chloride levels between the groups and no albumin was detected in any samples. These data suggest that stimulated parotid function may be a poor indicator of the extent of salivary involvement in individuals with autoimmune-mediated salivary gland disease.

Stimulation of mannose incorporation into rat osteoblastic osteosarcoma cells by parathyroid hormone.

Agents considered to alter cAMP accumulation in bone cells were evaluated for their effects on protein production and sugar incorporation by bone cells. Total protein production or mannose incorporation by cells and in media were measured by the amount of radioactivity incorporated into trichloroacetic-acid precipitable fractions. Incorporation of radioactive leucine into the cellular and secreted proteins was linear over 5 h; radioactive mannose incorporation was linear only up to 2 h. Cells were also incubated with selected agents and radioactive mannose or leucine for 2 h. Addition of parathyroid hormone (PTH), isoproterenol or dibutyryl cAMP to osteoblasts resulted in a significant increase in mannose incorporation; dibutyryl cGMP and butyric acid had no effect on mannose incorporation. None of the agents altered total protein production. Thus PTH stimulates mannose incorporation into osteoblasts and this effect is, at least in part, modulated by cAMP.

Marketing for patient retention.

Marketing has become an acceptable component of medical group management strategy. In their marketing efforts, most groups only concentrate on attracting new patients to the practice. Marketing to existing patients is an effective means to group prosperity, and it is less expensive and more ethical than trying to attract patients away from another medical group. Three key strategies for effectively marketing to existing patients are presented.

Uptake and secretion of technetium pertechnetate by the rat parotid gland.

The ability of acinar cells of the rat parotid gland to transport technetium pertechnetate (99mTcO-4) was examined. After intravenous injection, 99mTcO-4 was rapidly detected in parotid saliva. There was an excellent correlation between saliva and plasma 99mTcO-4 levels. The saliva to plasma ratio was always less than 1, consistent with the inability of rat parotid gland duct cells to concentrate the anion. Output of 99mTcO-4 by the parotid gland closely mimicked fluctuations in parotid saliva flow rate. In vitro, enzymatically dispersed parotid acinar cells accumulated 99mTcO-4 from the incubation medium in a biphasic manner. This uptake was partially blocked by 10(-4) M NaI. Cells which had accumulated 99mTcO-4 showed increased radionuclide efflux after exposure to 10(-5) M carbachol.

In vitro attachment of bacteria to extracts of cementum.

Cementum is a specialized mineralized tissue providing for the attachment of periodontal fibers to the root surface of a tooth. In periodontal disease this connective tissue attachment to the cemental surface is lost. The ability of bacteria to adhere to the root surface, an initial event in the disease process, may be influenced by the organic matrix of cementum. Therefore, an in vitro assay of cell attachment was modified to study bacterial adherence to protein extracts of cementum. Petri dishes coated with the extracts were pre-incubated in culture media and then bacteria were added. Using this assay, Capnocytophaga-like species, a gram negative bacterium implicated in periodontal disease, attached preferentially to dishes coated with cemental extracts when compared with Type I collagen or uncoated dishes. This assay system should prove beneficial for studying the attachment of various microorganisms to protein extracts of both normal and diseased cementum, as well as providing insight into the unique attachment properties of cementum.