Advances in the Acute and Preventive Treatment of Pediatric Migraine

PURPOSE OF REVIEW

Headaches are common in children and adolescents. Treatments for debilitating migraine are often not FDA approved or lack evidence of efficacy for children. This narrative review looks at the evidence for acute and preventative pharmacologic and non-pharmacologic treatment of pediatric migraine, as well as reviewing any recent or ongoing clinical trials.

RECENT FINDINGS

Studies have been published on pharmacological treatments for headache, as well as non-pharmacological treatments. Recent findings in pediatric migraine using onabotulinumtoxinA, calcitonin gene related peptide antagonists, interventional procedures, and devices are reviewed. Pharmacologic as well as non-pharmacologic approaches for the prevention and treatment of migraine show safety and efficacy data that is promising. These treatments should be incorporated in a multi-modal approach to the management of pediatric migraine. Continued studies, prospective and randomized, are needed to further assess these newer treatments for migraine in the pediatric setting.

The impact of different hair-removal behaviours on the biophysical and biochemical characteristics of female axillary skin

Objective

The impact of hair removal on the biophysical and biochemical characteristics of human axillary skin is not fully understood. This study investigated the effect of different hair‐removal techniques on biophysical parameters and the concentrations of key inflammatory biomarkers in the axillae of female Thai subjects. Axillary hair was removed by shaving, plucking or waxing.

Methods

Following a 2‐week washout phase without hair removal, subjects underwent visual assessment for erythema and skin dryness in one (randomized) axilla, then, hair was removed from the axilla by shaving, plucking or waxing according to each subject’s established habit. Erythema and dryness were assessed again 30 min after hair removal, and buffer scrubs collected from depilated and non‐depilated axillae and analysed for inflammatory cytokines; after a further 48 h, erythema, dryness and post‐inflammatory hyperpigmentation (PIHP) were assessed in the depilated axilla. Biophysical assessments (skin hydration, barrier integrity, elasticity and roughness) were made in depilated and non‐depilated axillae.

Results

All three hair‐removal techniques induced an increase in axillary erythema and skin dryness. Shaving was associated with significantly less erythema (P < 0.01), but significantly greater skin dryness (P < 0.05) versus the other techniques 30 min after hair removal. There were no between‐technique differences in PIHP or biophysical parameters. Interleukins IL‐1α and IL‐1RA concentrations increased, and IL‐8 concentration decreased following hair removal by each technique.

Conclusion

This is the first study to identify the principal cytokines associated with the inflammatory process triggered by axillary hair removal. A single hair‐removal treatment did not appear to induce PIHP or further biophysical changes to the skin.

VIP and muscarinic synergistic mucin secretion by salivary mucous cells is mediated by enhanced PKC activity via VIP-induced release of an intracellular Ca2+ pool

Mucin secretion by salivary mucous glands is mediated predominantly by parasympathetic acetylcholine activation of cholinergic muscarinic receptors via increased intracellular free calcium ([Ca²⁺]_i) and activation of conventional protein kinase C isozymes (cPKC). However, the parasympathetic co-neurotransmitter, vasoactive intestinal peptide (VIP), also initiates secretion, but to a lesser extent. In the present study, cross talk between VIP- and muscarinic-induced mucin secretion was investigated using isolated rat sublingual tubuloacini. VIP-induced secretion is mediated by cAMP-activated protein kinase A (PKA), independently of increased [Ca²⁺]_i. Synergistic secretion between VIP and the muscarinic agonist, carbachol, was demonstrated but only with submaximal carbachol. Carbachol has no effect on cAMP ± VIP. Instead, PKA activated by VIP releases Ca²⁺ from an intracellular pool maintained by the sarco/endoplasmic reticulum Ca²⁺-ATPase pump. Calcium release was independent of phospholipase C activity. The resultant sustained [Ca²⁺]_i increase is additive to submaximal, but not maximal carbachol-induced [Ca²⁺]_i. Synergistic mucin secretion was mimicked by VIP plus either phorbol 12-myristate 13-acetate or 0.01 μM thapsigargin, and blocked by the PKC inhibitor, Gö6976. VIP-induced Ca²⁺ release also promoted store-operated Ca²⁺ entry. Synergism is therefore driven by VIP-mediated [Ca²⁺]_i augmenting cPKC activity to enhance muscarinic mucin secretion. Additional data suggest ryanodine receptors control VIP/PKA-mediated Ca²⁺ release from a Ca²⁺ pool also responsive to maximal carbachol. A working model of muscarinic and VIP control of mucous cell exocrine secretion is presented. Results are discussed in relation to synergistic mechanisms in other secretory cells, and the physiological and therapeutic significance of VIP/muscarinic synergism controlling salivary mucous cell exocrine secretion.

Role of calcium and PKC in salivary mucous cell exocrine secretion

Fluid and exocrine secretion of mucins by salivary mucous glands is regulated predominantly by parasympathetic activation of muscarinic receptors. A direct role for subsequent putative signaling steps, phospholipase C (PLC), increased intracellular calcium ([Ca(2+)](i)), and isoforms of protein kinase C (PKC) in mediating muscarinic exocrine secretion has not been elucidated, and these are potential therapeutic targets to enhance mucin secretion in hyposalivary patients. We found that muscarinic-induced mucin secretion by rat sublingual tubulo-acini was dependent upon PLC activation and the subsequent increase in [Ca(2+)](i), and further identified a transient PKC-independent component of secretion dependent upon Ca(2+) release from intracellular stores, whereas sustained secretion required entry of extracellular Ca(2+). Interactions among carbachol, PKC inhibitors, phorbol 12-myristate 13-acetate, and thapsigargin to modulate [Ca(2+)](i) implicated conventional PKC isoforms in mediating sustained secretion. With increasing times during carbachol perfusion of glands, in situ, PKC-α redistributed across glandular membrane compartments and underwent a rapid and persistent accumulation near the luminal borders of mucous cells. PKC-β1 displayed transient localization near luminal borders, whereas the novel PKCs, PKC-δ or PKC-ε, displayed little or no redistribution in mucous cells. Collective results implicate synergistic interactions between diacylglycerol (DAG) and increasing [Ca(2+)](i) levels to activate cPKCs in mediating sustained muscarinic-induced secretion.

Effect of antiperspirants on whole body sweat rate and thermoregulation

It is well established that the evaporation of sweat from the human body surface is the main mechanism by which heat balance is maintained following a rise in body core temperature. Since the introduction of the first brand name antiperspirant in the United States during the early 1900s, antiperspirant products designed to control underarm wetness have grown to represent one of the largest cosmetic categories in most global markets. However, although axillary sweating only constitutes less than 1% of whole body sweat rate, consumers, particularly in hot countries, have begun to articulate the concern that antiperspirants may interfere with the body's natural cooling process. To investigate this, we undertook carefully designed experiments that measured the effects of axillary antiperspirant application on whole body sweat rate and body core temperature, following a regimen of exercise-induced heat stress in a hot environment in human volunteers. Our data show clearly that although antiperspirant prevents sweat production in the axillary area, this does not impact the ability of the body to thermoregulate following a rise in body core temperature. Thus, recent consumer questioning over this aspect of antiperspirant use appears to be unwarranted.

Survivorship of the St Georg Sled medial unicompartmental knee replacement beyond ten years

There have been several reports of good survivorship and excellent function at ten years with fixed-bearing unicompartmental knee replacement. However, little is known about survival beyond ten years. From the Bristol database of over 4000 knee replacements, we identified 203 St Georg Sled unicompartmental knee replacements (174 patients) which had already survived ten years. The mean age of the patients at surgery was 67.1 years (35.7 to 85) with 67 (38.5%) being under 65 years at the time of surgery. They were reviewed at a mean of 14.8 years (10 to 29.4) from surgery to determine survivorship and function. There were 99 knees followed up for 15 years, 21 for 20 years and four for 25 years. The remainder failed, were withdrawn, or the patient had died. In 58 patients (69 knees) the implant was in situ at the time of death. Revision was undertaken in 16 knees (7.9%) at a mean of 13 years (10.2 to 21.6) after operation. In seven knees (3.4%) this was for progression of arthritis, in three (1.5%) for wear of polyethylene, in four (2%) for tibial loosening, in two (1%) for fracture of the femoral component and in two (1%) for infection. Two knees (1%) were revised for more than one reason. The mean Bristol knee score of the surviving knees fell from 86 (34 to 100) to 79 (42 to 100) during the second decade. Survivorship to 20 years was 85.9% (95% CI 82.9% to 88.9%) and at 25 years was 80% (95% CI 70.2% to 89.8%). Satisfactory survival of a fixed-bearing unicompartmental knee replacement can be achieved into the second decade and beyond.

Hidden blood loss following hip and knee arthroplasty. Correct management of blood loss should take hidden loss into account

Following total hip arthroplasty (THA) and total knee arthroplasty (TKR) only the 'visible' measured blood loss is usually known. This underestimates the 'true' total loss, as some loss is 'hidden'. Correct management of blood loss should take hidden loss into account. We studied 101 THAs and 101 TKAs (with re-infusion of drained blood). Following THA, the mean total loss was 1510 ml and the hidden loss 471 ml (26%). Following TKA, the mean total loss was 1498 ml. The hidden loss was 765 ml (49%). Obesity made no difference with either operation. THA involves a small hidden loss, the total loss being 1.3 times that measured. However, following TKA, there may be substantial hidden blood loss due to bleeding into the tissues and residual blood in the joint. The true total loss can be determined by doubling the measured loss.

Hidden blood loss following hip and knee arthroplasty. Correct management of blood loss should take hidden loss into account

Following total hip arthroplasty (THA) and total knee arthroplasty (TKR) only the 'visible' measured blood loss is usually known. This underestimates the 'true' total loss, as some loss is 'hidden'. Correct management of blood loss should take hidden loss into account. We studied 101 THAs and 101 TKAs (with re-infusion of drained blood). Following THA, the mean total loss was 1510 ml and the hidden loss 471 ml (26%). Following TKA, the mean total loss was 1498 ml. The hidden loss was 765 ml (49%). Obesity made no difference with either operation. THA involves a small hidden loss, the total loss being 1.3 times that measured. However, following TKA, there may be substantial hidden blood loss due to bleeding into the tissues and residual blood in the joint. The true total loss can be determined by doubling the measured loss.

Lateral unicompartmental knee replacement survivorship and clinical experience over 21 years

We describe 88 knees (79 patients) with lateral unicompartmental osteoarthritis which had been treated by the St Georg Sled prosthesis. At a mean follow-up of nine years (2 to 21) 15 knees had revision surgery, nine for progression of arthritis, six for loosening, four for breakage of a component and four for more than one reason. Six patients complained of moderate or severe pain at the final follow-up. Only five knees were lost to follow-up in the 21-year period. We performed survivorship analysis on the group using revision for any cause as the endpoint. At ten years the cumulative survival rate was 83%, and at 15 years, when ten knees were still at risk, it was 74%. Based on our clinical results and survival rate the St Georg Sled may be considered to be a suitable unicompartmental replacement for isolated lateral compartment osteoarthritis.

Development and deployment of an internet-based data management system for use by the Asthma Clinical Research Network

Data management system development for the first Asthma Clinical Research Network (ACRN) study began at the data coordinating center (DCC) in May 1995 with the requirement for delivery of a production system by November 1995. Special methods had to be used to establish an internet local area network (LAN), place clinical client systems, and achieve an accelerated software development cycle. The development of a fully integrated data management system prior to the start of the study was not possible. Therefore an early analysis focused on identifying discrete groupings of data management functions that would allow development of distinct database modules to provide specific functionality such as subject randomization, subject registration, and data entry. The modules were categorized as either being associated with clinical centers or the DCC so that the clinical center modules could be developed and delivered to meet the start date of the study. In the second phase of development during the relatively slow patient-enrollment period, the DCC functional modules were delivered discretely over time. While at the time this development model was a necessity due to limited DCC resources, it continues to be used today as it permits the DCC to implement studies more rapidly and efficiently for the ACRN. This paper describes the methodologies used to develop an internet-based LAN, establish clinical center client systems, establish DCC client and server operations, and develop a data management system. It describes the circumstances that contributed to the development of these systems and the special methodologies developed. The technical aspects of the data management system and LAN are presented as well as a description of the requirements and constraints analysis used to develop the hardware and software systems.

Modem remote support of pulmonary-function testing and quality control systems

The data coordinating center (DCC) of the Asthma Clinical Research Network (ACRN) is responsible for the support of 11 pulmonary-function testing systems and two quality control systems. Pulmonary-function data from these systems are used as outcome indicators in studies conducted by the ACRN. Each of these systems is composed of a spirometer, a personal computer for data acquisition from the spirometer, a modem, and a printer. These systems are located at six clinical centers nationwide. An analysis conducted at the beginning of the first ACRN protocol identified the following requirements: (1) standard pulmonary-function testing, (2) standard methacholine-challenge testing, (3) the ability to handle simultaneous multiple protocols as well as have data from non-ACRN subjects, (4) the ability to separate data from different protocols as well as separate ACRN and non-ACRN data, (5) the ability to transmit data from the remote clinical centers to the DCC, (6) the ability to ensure quality data and to report on those results, and (7) the ability to provide remote support.

Comparison of subacute rehabilitative care with outpatient primary medical care

PURPOSE

Prior rehabilitation outcome studies have had many weaknesses. but they gradually observe a lack of long-term benefits from inpatient care alone. The goal of this study was to measure the additive effect of outpatient, subacute rehabilitation (compared with usual outpatient primary medical care) for adults diagnosed with a disabling disorder in four major diagnostic groups (nervous, circulatory, musculoskeletal and injury).

METHOD

A randomized clinical trial was conducted to determine the effects of outpatient, subacute rehabilitative care on: (1) physical function; (2) health; (3) well being; (4) family function; and (5) social support. Patients hospitalized for the first time with a disabling condition (n = 180) were provided inpatient rehabilitation and then were randomly assigned to either outpatient, subacute rehabilitation at home (n = 90) or to usual outpatient follow-up (n = 90) in which only primary care medical services were provided. To compare the two groups, univariate analyses of covariance were conducted for the outcome variables.

RESULTS

The major finding of this study was that of no significant effect of the intervention on any outcome variable.

CONCLUSIONS

Based on current study results, we conclude that any long term additive benefit of outpatient, subacute rehabilitation may not be detectable across disability categories and may require closer evaluation in studies with a more homogeneous population than in the current study. Providing complex follow-up case management services to all clients is apparently not beneficial and might better be provided using selection criteria based on need. Future studies should determine if services are more effective when provided to those with the most unmet rehabilitative needs. Further outpatient, subacute care rehabilitation studies should address the specific needs of the patients and be adapted individually to those needs.

Chronic pediatric asthma and chiropractic spinal manipulation: a prospective clinical series and randomized clinical pilot study

OBJECTIVES

The first objective was to determine if chiropractic spinal manipulative therapy (SMT) in addition to optimal medical management resulted in clinically important changes in asthma-related outcomes in children. The second objective was to assess the feasibility of conducting a full-scale, randomized clinical trial in terms of recruitment, evaluation, treatment, and ability to deliver a sham SMT procedure.

STUDY DESIGN

Prospective clinical case series combined with an observer-blinded, pilot randomized clinical trial with a 1-year follow-up period.

SETTING

Primary contact, college outpatient clinic, and a pediatric hospital.

PATIENTS

A total of 36 patients aged 6 to 17 years with mild and moderate persistent asthma were admitted to the study.

OUTCOME MEASURES

Pulmonary function tests; patient- and parent- or guardian-rated asthma-specific quality of life, asthma severity, and improvement; am and pm peak expiratory flow rates; and diary-based day and nighttime symptoms.

INTERVENTIONS

Twenty chiropractic treatment sessions were scheduled during the 3-month intervention phase. Patients were randomly assigned to receive either active SMT or sham SMT in addition to their standardized ongoing medical management.

RESULTS

It is possible to blind the participants to the nature of the SMT intervention, and a full-scale trial with the described design is feasible to conduct. At the end of the 12-week intervention phase, objective lung function tests and patient-rated day and nighttime symptoms based on diary recordings showed little or no change. Of the patient-rated measures, a reduction of approximately 20% in beta(2) bronchodilator use was seen (P =.10). The quality of life scores improved by 10% to 28% (P <.01), with the activity scale showing the most change. Asthma severity ratings showed a reduction of 39% (P <.001), and there was an overall improvement rating corresponding to 50% to 75%. The pulmonologist-rated improvement was small. Similarly, the improvements in parent- or guardian-rated outcomes were mostly small and not statistically significant. The changes in patient-rated severity and the improvement rating remained unchanged at 12-month posttreatment follow-up as assessed by a brief postal questionnaire.

CONCLUSION

After 3 months of combining chiropractic SMT with optimal medical management for pediatric asthma, the children rated their quality of life substantially higher and their asthma severity substantially lower. These improvements were maintained at the 1-year follow-up assessment. There were no important changes in lung function or hyperresponsiveness at any time. The observed improvements are unlikely as a result of the specific effects of chiropractic SMT alone, but other aspects of the clinical encounter that should not be dismissed readily. Further research is needed to assess which components of the chiropractic encounter are responsible for important improvements in patient-oriented outcomes so that they may be incorporated into the care of all patients with asthma.

Defective fluid secretion and NaCl absorption in the parotid glands of Na+/H+ exchanger-deficient mice

Multiple Na(+)/H(+) exchangers (NHEs) are expressed in salivary gland cells; however, their functions in the secretion of saliva by acinar cells and the subsequent modification of the ionic composition of this fluid by the ducts are unclear. Mice with targeted disruptions of the Nhe1, Nhe2, and Nhe3 genes were used to study the in vivo functions of these exchangers in parotid glands. Immunohistochemistry indicated that NHE1 was localized to the basolateral and NHE2 to apical membranes of both acinar and duct cells, whereas NHE3 was restricted to the apical region of duct cells. Na(+)/H(+) exchange was reduced more than 95% in acinar cells and greater than 80% in duct cells of NHE1-deficient mice (Nhe1(-/-)). Salivation in response to pilocarpine stimulation was reduced significantly in both Nhe1(-/-) and Nhe2(-/-) mice, particularly during prolonged stimulation, whereas the loss of NHE3 had no effect on secretion. Expression of Na(+)/K(+)/2Cl(-) cotransporter mRNA increased dramatically in Nhe1(-/-) parotid glands but not in those of Nhe2(-/-) or Nhe3(-/-) mice, suggesting that compensation occurs for the loss of NHE1. The sodium content, chloride activity and osmolality of saliva in Nhe2(-/-) or Nhe3(-/-) mice were comparable with those of wild-type mice. In contrast, Nhe1(-/-) mice displayed impaired NaCl absorption. These results suggest that in parotid duct cells apical NHE2 and NHE3 do not play a major role in Na(+) absorption. These results also demonstrate that basolateral NHE1 and apical NHE2 modulate saliva secretion in vivo, especially during sustained stimulation when secretion depends less on Na(+)/K(+)/2Cl(-) cotransporter activity.

What can transgenic and gene-targeted mouse models teach us about salivary gland physiology?

Thousands of genetically modified mice have been developed since the first reports of stable expression of recombinant DNA in this species nearly 20 years ago. This mammalian model system has revolutionized the study of whole-animal, organ, and cell physiology. Transgenic and gene-targeted mice have been widely used to characterize salivary-gland-specific expression and to identify genes associated with tumorigenesis. Moreover, several of these mouse lines have proved to be useful models of salivary gland disease related to impaired immunology, i.e., Sjögren's syndrome, and disease states associated with pathogens. Despite the availability of genetically modified mice, few investigators have taken advantage of this resource to better their understanding of salivary gland function as it relates to the production of saliva. In this article, we describe the methods used to generate transgenic and gene-targeted mice and provide an overview of the advantages of and potential difficulties with these models. Finally, using these mouse models, we discuss the advances made in our understanding of the salivary gland secretion process.

Nonoperative treatments for sciatica: a pilot study for a randomized clinical trial

OBJECTIVES

To assess the feasibility of patient recruitment, the ability of patients and clinicians to comply with study protocols, and the use of data collection instruments to collect cost-effectiveness data, and to obtain variability estimates for sample-size calculations for a full-scale trial.

STUDY DESIGN

Prospective, observer-blinded, pilot randomized clinical trial.

SETTING

Primary contact chiropractic and medical clinics.

PATIENTS

Ages 20 to 65 years, with low back-related radiating leg pain (sciatica).

OUTCOME MEASURES

Self-report questionnaires were administered at baseline and 3 and 12 weeks after randomization. The measures included leg and back pain severity, frequency and bothersomeness of symptoms, leg/back disability, medication use, global improvement, satisfaction, and health care utilization.

INTERVENTIONS

Medical care, chiropractic care, and epidural steroid injections.

RESULTS

A total of 706 persons were screened by phone to determine initial eligibility. Of these, over 90% of those persons contacted did not meet the entrance criteria. The most common reason for disqualification was that the duration of the complaint was longer than 3 months. Twenty patients were randomized into the study. All 3 groups showed substantial improvements in the main patient-rated outcomes at the end of the 12-week intervention phase. For leg pain, back pain, frequency and bothersomeness of leg symptoms, and Roland-Morris disability score, the percent improvement varied from 50% to 84%, and the corresponding effect sizes ranged from 0.8 to 2.2. Bothersomeness of leg symptoms was the most responsive outcome associated with the largest magnitude of effect size. All within-group changes from baseline were statistically significant (P <.01). No between-group comparisons were planned or performed because of the insufficient sample size and high risk of committing type I and type II errors.

CONCLUSIONS

Pilot studies such as these are important for the determination of the feasibility of conducting costly, larger scale trials. Recruitment for a full-scale study of sciatica of 2 to 12 weeks duration is not feasible, given the methods used in this pilot study. Our results do indicate, however, that there are substantial numbers of patients with sciatica more chronic in nature who would be interested in participating in a similar study. In addition, collaboration with a local health maintenance organization would likely facilitate clinician referrals and optimize the recruitment process. Patient and provider compliance was high in the pilot study, which indicates that most study protocols are feasible. Additionally, we were able to collect complete outcomes data, including those regarding health care use. A suggested modification by investigators and outside consultants has resulted in the replacement of the medication group with a minimal intervention control group (ie, self-care advice). As a result, a second pilot study of patients with sciatica of more than 4 weeks duration has been planned before a full-scale trial is attempted.

Severe impairment of salivation in Na+/K+/2Cl- cotransporter (NKCC1)-deficient mice

The salivary fluid secretory mechanism is thought to require Na(+)/K(+)/2Cl(-) cotransporter-mediated Cl(-) uptake. To directly test this possibility we studied the in vivo and in vitro functioning of acinar cells from the parotid glands of mice with targeted disruption of Na(+)/K(+)/2Cl(-) cotransporter isoform 1 (Nkcc1), the gene encoding the salivary Na(+)/K(+)/2Cl(-) cotransporter. In wild-type mice NKCC1 was localized to the basolateral membranes of parotid acinar cells, whereas expression was not detected in duct cells. The lack of functional NKCC1 resulted in a dramatic reduction (>60%) in the volume of saliva secreted in response to a muscarinic agonist, the primary in situ salivation signal. Consistent with defective Cl(-) uptake, a loss of bumetanide-sensitive Cl(-) influx was observed in parotid acinar cells from mice lacking NKCC1. Cl(-)/ HCO(3)(-) exchanger activity was increased in parotid acinar cells isolated from knockout mice suggesting that the residual saliva secreted by mice lacking NKCC1 is associated with anion exchanger-dependent Cl(-) uptake. Indeed, expression of the Cl(-)/ HCO(3)(-) exchanger AE2 was enhanced suggesting that this transporter compensates for the loss of functional Na(+)/K(+)/2Cl(-) cotransporter. Furthermore, the ability of the parotid gland to conserve NaCl was abolished in NKCC1-deficient mice. This deficit was not associated with changes in the morphology of the ducts, but transcript levels for the alpha-, beta-, and gamma-subunits of the epithelial Na(+) channel were reduced. These data directly demonstrate that NKCC1 is the major Cl(-) uptake mechanism across the basolateral membrane of acinar cells and is critical for driving saliva secretion in vivo.

Program review of community residential care

This article provides an overview of the Department of Veterans Affairs Community Residential Care Program and summarizes key literature about programs developed in the United States. Descriptive data for 1995 and 1996 are provided to assist program planners in comparing and contrasting client characteristics and services. The authors conclude that, in addition to being cost effective, the residential care program strengthens relationships between the health care facility and the community it serves.

Persistence of p53 mutations and resistance of keratinocytes to apoptosis are associated with the increased susceptibility of mice lacking the XPC gene to UV carcinogenesis

Like xeroderma pigmentosum (XP) patients, transgenic mice lacking nucleotide excision repair (NER) genes such as XPA and XPC are extremely susceptible to ultraviolet (UV)-induced skin cancer. Because the p53 gene is an important target for UV carcinogenesis and because the p53 protein modulates NER, we investigated the consequences of NER deficiency on UV-induced p53 mutations in XPC-/- mouse skin tumors. Thirty-eight (76%) of 50 UV-induced XPC-/- skin tumor analysed displayed C-->T or CC-->TT transitions at dipyrimidine sites on the untranscribed strand of the p53 gene. A major hot spot for p53 mutation occurred at codon 270, which is also a hot spot in UV-induced skin tumors from NER-proficient C3H and SKH-hr 1 mice. Interestingly, codon 270 mutations were induced in both XPC-/- and +/+ mouse skin after 1 week of UV irradiation, but the mutations persisted only in XPC-/- mouse skin after 3 - 4 weeks of chronic UV. The persistence of UV-induced p53 mutations in XPC-/- mouse skin was associated with decreased apoptosis and increased proliferation of keratinocytes, suggesting that these events may contribute to the accelerated development of UV-induced skin tumors in XPC-/- mice.

Asymmetric Electrical Structure in the Mantle Beneath the East Pacific Rise at 17 degrees S

The magnetotelluric component of the Mantle Electromagnetic and Tomography (MELT) Experiment measured the electrical resistivity structure of the mantle beneath the fast-spreading southern East Pacific Rise (EPR). The data reveal an asymmetric resistivity structure, with lower resistivity to the west of the ridge. The uppermost 100 kilometers of mantle immediately to the east of the ridge is consistent with a dry olivine resistivity structure indicating a mantle depleted of melt and volatiles. Mantle resistivities to the west of the ridge are consistent with a low-melt fraction (about 1 to 2 percent interconnected melt) distributed over a broad region and extending to depths of about 150 kilometers. The asymmetry in resistivity structure may be the result of asymmetric spreading rates and a westward migration of the ridge axis and suggests distinct styles of melt formation and delivery in the mantle beneath the two plates.

Targeted disruption of the Nhe1 gene prevents muscarinic agonist-induced up-regulation of Na(+)/H(+) exchange in mouse parotid acinar cells

The onset of salivary gland fluid secretion in response to muscarinic stimulation is accompanied by up-regulation of Na(+)/H(+) exchanger (NHE) activity. Although multiple NHE isoforms (NHE1, NHE2, and NHE3) have been identified in salivary glands, little is known about their specific function(s) in resting and secreting acinar cells. Mice with targeted disruptions of the Nhe1, Nhe2, and Nhe3 genes were used to investigate the contribution of these proteins to the stimulation-induced up-regulation of NHE activity in mouse parotid acinar cells. The lack of NHE1, but not NHE2 or NHE3, prevented intracellular pH recovery from an acid load in resting acinar cells, in acini stimulated to secrete with the muscarinic agonist carbachol, and in acini shrunken by hypertonic addition of sucrose. In HCO(3)(-)-containing solution, the rate of intracellular pH recovery from a muscarinic agonist-stimulated acid load was significantly inhibited in acinar cells from mice lacking NHE1, but not in cells from NHE2- or NHE3-deficient mice. These data demonstrate that NHE1 is the major regulator of intracellular pH in both resting and muscarinic agonist-stimulated acinar cells and suggest that up-regulation of NHE1 activity has an important role in modulating saliva production in vivo.

A feasibility study of chiropractic spinal manipulation versus sham spinal manipulation for chronic otitis media with effusion in children

BACKGROUND

Pediatric otitis media with effusion is a common and costly condition. Although chiropractors have anecdotally claimed success in treating otitis media, there is little research to support their claims.

OBJECTIVE

A pilot study was undertaken for the purpose of assessing the feasibility of conducting a full-scale randomized clinical trial investigating the efficacy of chiropractic spinal manipulative therapy (SMT) for children with chronic otitis media with effusion.

METHODS

This study was a prospective, parallel-group, observer-blinded, randomized feasibility study. Twenty-two patients, ages 6 months to 6 years, received either active chiropractic SMT or placebo chiropractic SMT. Otoscopy and tympanometry were used to create a middle ear status profile, and daily diaries were collected.

RESULTS

Five newspaper advertisements over 6 months generated 105 responses. Twenty patients subsequently qualified and were randomized into the study. Collection of tympanometric and otoscopic data proved to be challenging. Compliance with the treatment and evaluation protocols and daily diaries was excellent. There were no reports of serious side effects as a result of either the active or placebo chiropractic treatments.

CONCLUSION

Recruitment for a randomized controlled trial is feasible and could be enhanced by medical collaboration. Patients and parents are able and willing to participate in a study comparing active SMT and placebo SMT. Parents were extremely compliant with the daily diaries, suggesting that similar quality-of-life and functional status measures can be successfully used in a larger trial. We found the objective outcomes assessment involving tympanometry and otoscopy extremely challenging and should be performed by experienced examiners in future studies.

Ion transport and signalling in human labial glands

Recent reports characterizing the physiological properties of normal human labial acini are reviewed with particular emphasis on mechanisms related to fluid secretion. In contrast to the salivary glands of several experimental animals, human labial acinar cells do not appear to have a1-adrenergic receptors, substance P peptidergic receptors, or significant levels of Cl-/HCO3- exchange. Nor do they appear to secrete HCO3- in response to Ca2+ mobilizing stimuli. The data presently available indicates that fluid secretion by these glands is mainly under muscarinic control and is due to acinar Cl- secretion driven by a basolateral Na+ -K+ -2Cl- cotansporter.

Perceived functional health of disabled elderly persons in a follow-up program for primary care

180 disabled elderly persons were followed in a home care program after acute care rehabilitation in order to correlate subjective and objective ratings of medical, physical, and social functioning. To assess the benefits of case management services, 95 test patients receiving such care at home were compared with 85 controls who did not receive services. Both groups reported gains in functional health and their reports were verified with objective measures. There was no difference, however, between the groups in outcome. Our findings indicated that self-assessments correlate highly with measures of functional health. Procedures for self-ratings should be developed as important complements to objective functional health measures.

Targeted disruption of the murine Nhe1 locus induces ataxia, growth retardation, and seizures

In most cells, the ubiquitously expressed Na+/H+ exchanger isoform 1 (NHE1) is thought to be a primary regulator of pH homeostasis, cell volume regulation, and the proliferative response to growth factor stimulation. To study the function of NHE1 during embryogenesis when these cellular processes are very active, we targeted the Nhe1 gene by replacing the sequence encoding transmembrane domains 6 and 7 with the neomycin resistance gene. NHE activity assays on isolated acinar cells indicated that the targeted allele is functionally null. Although the absence of NHE1 is compatible with embryogenesis, Nhe1 homozygous mutants (-/-) exhibit a decreased rate of postnatal growth that is first evident at 2 wk of age. At this time, Nhe1 -/- animals also begin to exhibit ataxia and epileptic-like seizures. Approximately 67% of the -/- mutants die before weaning. Postmortem examinations frequently revealed an accumulation of a waxy particulate material inside the ears, around the eyes and chin, and on the ventral surface of the paws. Histological analysis of adult tissues revealed a thickening of the lamina propria and a slightly atrophic glandular mucosa in the stomach.

Radiation-induced progressive decrease in fluid secretion in rat submandibular glands is related to decreased acinar volume and not impaired calcium signaling

The mechanism(s) of radiation-induced salivary gland dysfunction is poorly understood. In the present study, we have assessed the secretory function (muscarinic agonist-stimulated saliva flow, intracellular calcium mobilization, Na+/K+/2Cl- cotransport activity) in rat submandibular glands 12 months postirradiation (single dose, 10 Gy). The morphological status of glands from control and irradiated rats was also determined. Pilocarpine-stimulated salivary flow was decreased by 67% at 12 months (but not at 3 months) after irradiation. This was associated with a 47% decrease in the wet weight of the irradiated glands. Histological and morphometric analysis demonstrated that acinar cells were smaller and occupied relatively less volume and convoluted granular tubules were smaller but occupied the same relative volume, while intercalated and striated ducts maintained their size but occupied a greater relative volume in submandibular glands from irradiated compared to control animals. In addition, no inflammation or fibrosis was observed in the irradiated tissues. Carbachol- or thapsigargin-stimulated mobilization of Ca2+ was similar in dispersed submandibular gland cells from control and irradiated animals. Further, [Ca2+]i imaging of individual ducts and acini from control and irradiated groups showed, for the first time, that mobilization of Ca2+ in either cell type was not altered by the radiation treatment. The carbachol-stimulated, bumetanide-sensitive component of the Na+/K+/ 2Cl- cotransport activity was also similar in submandibular gland cells from control and irradiated animals. These data demonstrate that a single dose of gamma radiation induces a progressive loss of submandibular gland tissue and function. This loss of salivary flow is not due to chronic inflammation or fibrosis of the gland or an alteration in the neurotransmitter signaling mechanism in the acinar or ductal cells. The radiation-induced decrease in fluid secretion appears to be related to a change in either the water-handling capacity of the acini or the number of acinar cells in the gland.

Hospital-based rehabilitative care versus outpatient services: effect on functioning and health status

PURPOSE

The goal of this clinical trial was to examine the long-term impact of rehabilitative care on the health status of patients diagnosed with a disabling disorder.

METHOD

Study patients consisted of first-time hospitalizations from diagnostic groups commonly admitted for inpatient rehabilitation, including nervous, circulatory, and musculoskeletal disorders or injury. Patients were randomly assigned to inpatient rehabilitation (n = 43) or to outpatient follow-up (n = 42) in which the usual medical services were provided but no scheduled rehabilitative therapies were offered. Specific objectives of the study were to determine the effects of impatient rehabilitation on: (1) functional ability, (2) health and mental health status, (3) personal adjustment, and (4) family function. Cost and use of health-care resources were descriptively assessed.

RESULTS

Analysis of covariance found no significant treatment effects, either at 6 months or at 1 year, for any of the variables under study. In addition, there were no differences between groups in their use of nursing homes, length of hospital stay, mortality, or in the number of hospital readmissions or clinic visits during the first year after hospital discharge. Use of rehabilitation services and cost of care was significantly higher than outpatient services. The findings were consistent with previous studies for most outcomes, with the major exception being functional improvements. Contrary to earlier studies, rehabilitation was not found to effectively produce lasting functional outcomes. However, study conditions may not have fully corresponded to those of previous studies, and further research is needed. The patient sample was representative of a full inpatient service and therefore more heterogeneous than samples reported in prior studies, but the small sample size (due to reductions in the number of admitted patients to the rehabilitation unit during the course of the study) precluded subgroup analysis of diagnostic groupings.

CONCLUSION

The findings suggest that hospital-based rehabilitative care does not have lasting benefits, and that alternative care or supportive follow-up by a subacute-care facility may be needed to assist patients in maintaining functional gains and health benefits.

New insights into the upregulation and function of the salivary Na+-K+-2Cl- cotransporter

In many exocrine epithelia, the Na+-K+-2Cl- cotransporter is the main provider of cellular chloride entry during transepithelial salt and water secretion. Because of its accessibility and hormonal responsiveness, the salivary gland has recently emerged as a convenient preparation in which to study the regulation and characteristics of this transport protein. In this review, we summarize recent findings from our laboratory which demonstrate that muscarinic, alpha1-adrenergic and peptidergic stimulation of rat parotid acinar cells induce a dramatic (up to twenty-fold) upregulation of Na+-K+-2Cl- cotransporter activity. Our results indicate that this effect is dependent on the rise in intracellular calcium concentration ([Ca2+]i) that accompanies stimulation, and is not a consequence of the KCl loss and the concomitant cell shrinkage associated with fluid secretion. In addition, we show that the effect of muscarinic stimulation on the cotransporter can be blocked by inhibitors of phospholipase A2, by a general inhibitor of arachidonic acid metabolism, and by specific inhibitors of the cytochrome P450 pathway. These data argue strongly for the involvement of a product of the cytochrome P450 pathway of arachidonic acid metabolism in upregulation of the salivary Na+-K+-2Cl- cotransporter.

In vitro studies of the regulation of mucous gland secretion

Our laboratory is concerned with elucidation of mechanisms regulating the exocrine secretion of mucin glycoproteins by mucous cells of salivary mucous glands. As a model system for our studies we use short-term cultures of acinar structures isolated from rat sublingual glands. Recent results are discussed from an on-going study of cross-talk between the two primary signaling pathways regulating exocrine secretion from isolated sublingual acini: the muscarinic cholinergic and vasoactive intestinal peptide (VIP) pathways. The combination of muscarinic agonist (carbachol) and VIP elicits a secretion equivalent to about 150% of the additive sum of the secretory responses to each agonist alone. This synergistic secretory response is only observed at submaximal concentrations of carbachol. VIP thus serves to decrease the EC50 for carbachol nearly three-fold. Results are thus far consistent with the hypothesis that a sustained rise in the intracellular concentration of calcium ions induced by VIP accounts for synergistic secretion and the heightened sensitivity to carbachol.

Evidence for a physiological role of NH4+ transport on the secretory Na(+)-K(+)-2Cl- cotransporter

The secretory Na(+)-K(+)-2Cl- cotransporter in salivary acinar cells is responsible for driving the transepithelial Cl- fluxes that give rise to fluid secretion. We demonstrate that the application of the muscarinic agonist carbachol to rat parotid acini results in an intracellular acid load that can be blocked by bumetanide, a specific inhibitor of the cotransporter. One component of this bumetanide-sensitive acid load is ouabain-sensitive while a second is dependent on the presence of sub-millimolar concentrations of NH4+ in our media. Our data indicate that this latter effect arises from NH4+ entry on the cotransporter operating in a Na(+)-NH4(+)-2Cl- cotransport mode and that at physiological NH4+ levels in the rat (approximately 0.1 mM), 10-15% of the acinar Cl- entry occurs via this route. We suggest that Na(+)-NH4(+)-2Cl- cotransport may also play a significant physiological role in other cell types and that this mode of operation of the secretory Na(+)-K(+)-2Cl- cotransporter could account for the currently unexplained presence of this protein in a number of tissues.

p53 Mutations in hairless SKH-hr1 mouse skin tumors induced by a solar simulator

In this study, we investigated whether the spectrum of p53 mutations in skin tumors induced in hairless SKH-hr1 mice by a solar simulator (290-400 nm) are similar to those found in skin tumors induced in C3H mice by UV radiation from unfiltered (250-400 nm) and Kodacel-filtered (290-400 nm) FS40 sunlamps. Analysis of tumor DNA for p53 mutations revealed that 14 of 16 (87.5%) SkH-hr1 skin tumors induced by the solar simulator contained mutations. Single C-->T transitions at dipyrimidine sequences located on the nontranscribed DNA strand were the most predominant type of p53 mutation. Remarkably, 52% of all p53 mutations in solar simulator-induced SKH-hr1 skin tumors occurred at codon 270, which is also a hotspot in C3H skin tumors induced by unfiltered and Kodacel-filtered FS40 sunlamps. However, T-->G transversions, which are hallmarks of UVA-induced mutations, were not detected in any of the solar simulator-induced skin tumors analyzed. These results demonstrate that the p53 mutation spectra seen in solar simulator-induced SKH-hr1 skin tumors are similar to those present in -unfiltered and Kodacel-filtered FS40 sunlamp-induced C3H skin tumors. In addition, our data indicate that the UVA present in solar simulator radiation does not play a role in the induction of p53 mutations that contribute to skin cancer development.

Molecular analysis of the human vitamin D binding protein (group specific component, Gc) in tuberous sclerosis complex (TSC)

Group specific component (Gc) is an abundant plasma protein whose functional role is not clearly established. Gc protein is synthesised in the liver and is known to bind vitamin D, vitamin D metabolites, and G actin; Gc protein is also implicated in macrophage activation. Several polymorphic electrophoretic variants of Gc protein are found in all human populations; the most common alleles are Gc-1f, Gc-1s, and Gc-2. In previous studies, Gc allele frequencies, determined using isoelectric focusing or immunofixation or both, were significantly different in patients with tuberous sclerosis complex (TSC) from matched controls, with an excess of Gc-2 in patients. Linkage association between Gc and TSC is unlikely since the Gc locus maps to chromosome 4q12, whereas the two common forms of TSC map to 9q34 and 16p13.1, respectively. However, a direct cause and effect relationship between Gc protein and TSC symptoms is possible. To investigate further the relationship between the Gc locus and TSC, two Gc restriction site polymorphisms, HaeIII and StyI, were typed in 43 unrelated white subjects with TSC. The frequencies of the restriction site polymorphisms in the TSC patients did not differ from those in control populations. Therefore a direct association between Gc type and TSC is unlikely. The previously reported association was either spurious or the result of typing errors in plasma from subjects with underlying abnormalities in plasma proteins.

Sunlight and skin cancer: inhibition of p53 mutations in UV-irradiated mouse skin by sunscreens

UV-induced mutations in the p53 tumor suppressor gene play an essential role in skin cancer development. We report here that such mutations can be detected in UV-irradiated mouse skin months before the gross appearance of skin tumors. Application of SPF-15 sunscreens to mouse skin before each UV irradiation nearly abolished the frequency of p53 mutations. These results indicate that p53 mutation is an early event in UV skin carcinogenesis and that inhibition of this event may serve as an early end point for assessing protective measures against skin cancer development.

Evidence that up-regulation of the parotid Na(+)-K(+)-2Cl- cotransporter by hypertonic shrinkage is not duplicated by isotonic shrinkage

The application of Ca2+ mobilizing secretagogues to rat parotid acini results in a significant decrease in cell volume (15-30%) due to isotonic salt loss. It is often assumed that the effects of such an isotonic volume decrease can be mimicked by anisotonic cell shrinkage. We demonstrate that the Na(+)-K(+)-2Cl- cotransporter in these cells is up-regulated by Ca2+ mobilizing secretagogues as well as by cell shrinkage in hypertonic media. However, we find that although the protein kinase inhibitors staurosporine (0.3 microM) and K252a (0.6 microM) significantly blunt the latter up-regulation, they are without effect on the former. These observations suggest that hypertonic and isotonic shrinkage do not result in the activation of the same intracellular signalling pathways, and indicate that anisotonic volume perturbations may not provide good experimental models of physiologic isotonic volume changes.

Upregulation of Na(+)-K(+)-2Cl- cotransporter activity in rat parotid acinar cells by muscarinic stimulation

1. The effects of fluid secretory stimuli on the Na(+)-K(+)-2Cl- cotransporter in rat parotid acini were investigated. Cotransporter activity was measured using NH4+ as a K+ surrogate and following cotransporter-mediated NH4+ fluxes by monitoring intracellular pH. 2. A dramatic upregulation (15- to 20-fold) of acinar Na(+)-K(+)-2Cl- cotransporter activity was induced by muscarinic, alpha 1-adrenergic and peptidergic stimuli. A half-maximal effect of the muscarinic agonist carbachol was observed at approximately 0.5 microM. 3. Our results indicate that the rise in intracellular calcium concentration ([Ca2+]i) which accompanies these stimuli is both a necessary and a sufficient condition for this effect; but it is not a consequence of the KCl loss and concomitant isotonic shrinkage caused by increased [Ca2+]i as it persists when these effects are prevented. 4. The effect of muscarinic stimulation on the cotransporter can, however, be blocked by inhibitors of phospholipase A2 (4-bromophenacylbromide and manoalide), by a general inhibitor of arachidonic acid metabolism (5,8,11,14-eicosatetraynoic acid) and by specific inhibitors of the cytochrome P450 pathway (methoxsalen and ketoconazole). 5. These latter results argue strongly for the involvement of a product of the cytochrome P450 pathway of arachidonic acid metabolism in upregulation of the salivary Na(+)-K(+)-2Cl- cotransporter. 6. Owing to the complexity of the arachidonic acid cascade a wide variety of agents could potentially interfere with this upregulation of the cotransporter, and thereby result in decreased salivary fluid production. We suggest that such an effect could underlie the dry mouth (xerostomia) that occurs as an unexplained side-effect of many commonly prescribed medications.

Copper-binding proteins in ectomycorrhizal fungi

The presence of copper-binding proteins produced in response to added copper was examined in isolates of Laccaria laccata (Scop, ex Fr.) Cooke and Paxillus involutus (Batsch ex Fr.) Fr. taken from copper-contaminated and uncontaminated sites, and in a single isolate of Scleroderma citrinum Pers. from a contaminated site. Two isolates of Laccaria (GLac4 and ELacl) grew better in 1-5 miu and 2-5 niM copper than a third (Lac3G) and were considered to be more tolerant. Amongst five isolates of P. involutus, three (WJPax2R, GPaxRSp2 and Pax4) were capable of growth in media containing 4-0 mM copper and were regarded as tolerant. All isolates of both Laccaria and Paxillus were capable of some growth in 2-5 mM copper, but S. citrinum was much more copper-sensitive and the concentration had to be reduced at least 10-fold before any growth occurred. Tolerance of isolates was not related to whether they were taken from copper-contaminated or uncontaminated sites. Copper-binding proteins were detected in response to copper in the culture media in the two tolerant isolates of Laccaria (GLac4 and ELacl) but not in the least tolerant isolate. In Paxillus, similar proteins were found in two tolerant isolates (GPaxRSp2 and Pax4) but not in WJPax2R, which was also regarded as tolerant, nor in any of the less tolerant isolates. Copper-binding proteins were not detected in S. citrinum. The copper-binding protein purified from the Laccaria isolate ELacl appeared as a single band in modified SDS-PAGE electrophoresis. Its molecular mass and spectral characteristics were consistent with it being a metallothionein.

Evaluating rehabilitation medicine: effects on survival, function, and home care

The goal of this study was to measure the clinical impact of rehabilitation on adults diagnosed with a disabling disorder in four major diagnostic groups (nervous, circulatory, musculoskeletal, and injury). To summarize the current knowledge in this area, a meta-analysis of rehabilitation studies was also completed. Specific objectives of the clinical trial were to determine the effects of inpatient rehabilitation on: (1) survival, (2) function, (3) home care, and related variables such as family function and use of health care resources. Patients hospitalized for the first time with a disabling condition (n = 85) were randomly assigned to inpatient rehabilitation (n = 43) or to outpatient follow-up (n = 42) in which the usual medical services were provided but no scheduled rehabilitative therapies were offered. To compare the two groups, analyses of covariance were conducted for functional ability, health care use, survival, health status, personal adjustment and family function. The between subjects factor was inpatient rehabilitation versus the control group. The within subjects factor was time of assessment (index, six months, and 1 year). No significant treatment effect was found at six months or one year for any of the variables under study using analyses of covariance. There were also no differences between groups in their use of nursing homes, length of hospital stay, survival, or in the number of hospital readmissions or clinic visits during the first year after hospital discharge. Rehabilitation did cost significantly more than medical care, primarily due to the cost of inpatient services. Some clinical trials have noted a treatment effect on functional ability but not on mortality, need for skilled care, or mental health status. The current study is consistent with these previous findings except for the lack of impact on physical function. This exception may be due to the fact that prior studies looked only at homogeneous groups, whereas the current study utilized heterogeneous grouping across four major diagnostic categories. Any apparent benefit may not be detectable across disability groups and may require more specialized scrutiny, or even tailored rehabilitative care, to detect a difference. It is recommended that health care systems evaluate the benefits of subacute rehabilitative care and consider outpatient programs that can be provided at home for implementation.

Meta-analysis with longitudinal studies: controlling for analytical bias

A recent study published in an international medical journal presented an opportunity to demonstrate the difficulties of interpreting meta-analysis results with longitudinal data. We conducted a new meta-analysis using identical data from the published study and showed contradictory results.

Interactions between secretin and acetylcholine in the regulation of fluid secretion by isolated rat pancreatic ducts

1. Interlobular ducts were isolated from the rat pancreas and maintained in short-term tissue culture. Fluid secretion from these isolated ducts was measured using micropuncture techniques, intracellular calcium concentration ([Ca2+]i) by fura-2 microspectrofluorimetry, and cyclic AMP by radioimmunoassay. 2. Applying secretin and ACh simultaneously to ducts caused either a stimulation or an inhibition of fluid secretion depending on the doses employed. 3. The inhibitory effect of secretin and ACh could be relieved by atropine, and by the protein kinase C (PKC) inhibitors staurosporine and 1-(5-isoquinolinylsulphonyl)-2-methyl-piperazine (H-7). 4. Activation of PKC by 12-O-tetradecanoylphorbol-13-acetate (TPA) and phorbol 12, 13-dibutyrate (PDBu) inhibited secretin-evoked fluid secretion. 5. ACh and TPA also inhibited fluid secretion stimulated by the adenylate cyclase activator, forskolin. 6. Neither secretin nor the PKC activators and inhibitors had any effect on either the increase in [Ca2+]i evoked by ACh or the increase in intracellular cyclic AMP evoked by secretin and forskolin. 7. We conclude that the inhibitory effect of combined doses of secretin and ACh on ductal fluid secretion is probably mediated by PKC at a point in the secretory mechanism distal to the generation of intracellular messengers.

Transfection of Syk protein tyrosine kinase reconstitutes high affinity IgE receptor-mediated degranulation in a Syk-negative variant of rat basophilic leukemia RBL-2H3 cells

Aggregation of the high affinity receptor for immunoglobulin E (Fc epsilon RI) on mast cells results in rapid tyrosine phosphorylation and activation of Syk, a cytoplasmic protein tyrosine kinase. To examine the role of Syk in the Fc epsilon RI signaling pathway, we identified a variant of RBL-2H3 cells that has no detectable Syk by immunoblotting and by in vitro kinase reactions. In these Syk-deficient TB1A2 cells, aggregation of Fc epsilon RI induced no histamine release and no detectable increase in total cellular protein tyrosine phosphorylation. However, stimulation of these cells with the calcium ionophore did induce degranulation. Fc epsilon RI aggregation induced tyrosine phosphorylation of the beta and gamma subunits of the receptor, but no increase in the tyrosine phosphorylation of phospholipase C-gamma 1 and phospholipase C-gamma 2 and no detectable increase in intracellular free Ca2+ concentration. By transfection, cloned lines were established with stable expression of Syk. In these reconstituted cells, Fc epsilon RI aggregation induced tyrosine phosphorylation of phospholipase C-gamma 1 and phospholipase C-gamma 2, an increase in intracellular free Ca2+ and histamine release. These results demonstrate that Syk plays a critical role in the early Fc epsilon RI-mediated signaling events. It further demonstrates that Syk activation occurs downstream of receptor phosphorylation, but upstream of most of the Fc epsilon RI-mediated protein tyrosine phosphorylations.

Elevation of intracellular cAMP by noradrenaline and vasoactive intestinal peptide in striated ducts isolated from the rabbit mandibular salivary gland

Salivary gland intralobular ducts are responsible for the modification of the electrolyte composition of the primary fluid secreted by the acini. However, the intracellular messengers that regulate this and other intralobular duct cell processes have not been fully characterized. To investigate the possibility that cAMP-mobilizing agonists may be involved, intralobular (striated) ducts were isolated from the rabbit mandibular salivary gland by tissue dissociation and microdissection and maintained in tissue culture overnight. Individual duct fragments were stimulated with the secretory agonists noradrenaline, vasoactive intestinal peptide (VIP) and substance P and their cAMP content measured by acetylated radioimmunoassay. Both noradrenaline and VIP elevated intracellular cAMP content concentration dependently, but substance P did not. The response to noradrenaline was blocked by the beta-adrenoceptor antagonist propranolol, but not by the alpha-adrenoceptor antagonist prazosin. Application of the VIP analogue [D-p-Cl-Phe6, Leu17]-VIP decreased the VIP-induced cAMP response. These results demonstrate that striated intralobular duct cells possess beta-adrenoceptors and peptidergic receptors that are coupled to adenylate cyclase and activated by noradrenaline and VIP, respectively. By elevating ductal cAMP content, these agonists may regulate both the electrolyte content of the primary saliva and the secretion of protein(s) from the ducts.

Risk screening for adverse outcomes in subacute care

Purpose of this study was to identify variables near hospital admission that could identify patients at risk for placement, death, or readmission. The goals were to assess sensitivity and specificity of screening strategies in predicting adverse outcomes that deter or affect home health care. We evaluated whether generic screens might efficiently identify type of outcome. Criteria reported in the literature were used to predict outcomes for 1,332 admissions. Factors that discriminated type of outcome included comorbidity, mental status, living arrangement, transfer to special care, prior admission, iatrogenic trauma, and pending litigation. We conclude risk scores can accurately predict outcome of hospital treatment, which may be useful in targeting patients for intervention. Using billing data, although rather insensitive, was the most cost-effective strategy.

Ion transport systems in human labial acinar cells

Human labial acini were assayed for the presence of ion transport systems associated with salivary fluid secretion using microfluorometric methods. Na(+)-K(+)-Cl- contransport and Na+/H+ exchange activities (determined by their bumetanide and amiloride sensitivities, respectively) were found at levels approximately 50% of those seen in similarly assayed rat parotid acini, but little, if any, C1-/HCO3-exchange activity was observed. Also, when human labial acini were stimulated with the muscarinic agonist carbachol, little evidence of the intracellular acidification associated with HCO3- secretion by other salivary glands was found. Na+/H+ exchange activity in human labial acini was downregulated (approximately 40%) by beta-adrenergic stimulation and upregulated (approximately threefold) by muscarinic stimulation. In contrast, beta-adrenergic stimulation produced only a marginally significant increase in Na(+)-K(+)-Cl- cotransport activity, and muscarinic stimulation was without effect. We include that basolateral Na(+)-K(+)-Cl- cotransport appears to be the dominant mechanism driving Cl- secretion and thereby fluid secretion in this tissue.

Intravenous theophylline in pediatric status asthmaticus. A prospective, randomized, double-blind, placebo-controlled trial

This study was conducted to determine whether intravenous theophylline, added to inhaled albuterol and intravenous methylprednisolone, provides a clinically significant benefit in the treatment of pediatric status asthmaticus. Patients aged 2 to 10 years were randomized to receive either intravenous theophylline or placebo. All patients received aerosolized albuterol and intravenous methylprednisolone. There was no difference between groups in the improvement of a clinical asthma score over time, in oxygen requirement, or in the number of albuterol treatments required. Theophylline group patients experienced more nausea, emesis, and insomnia. We conclude that there is no benefit in adding theophylline to treatment with methylprednisolone and albuterol for pediatric status asthmaticus. Furthermore, there are significantly more adverse effects associated with the use of theophylline.

Intracellular calcium transients in suctorian protozoa (Trichophrya spp.): correlation with spontaneous tentacle contractions

The luminescent photoprotein aequorin was used to measure intracellular free Ca2+ in three species of suctorian protozoon, Trichophrya riederi, Trichophrya collini and Trichophrya rotunda. Resting [Ca2+]i ranged from about 75-110 nM, and was unaffected by a change in temperature of the perfusate. Spontaneous Ca2+ transients were observed in all three species, with peak amplitudes ranging from 100-600 nM. In T. riederi and T. rotunda, three categories of transient (small, intermediate, large) were recorded; T. collini displayed only small transients. In both T. riederi and T. collini, raising the temperature from 5 degrees to 26 degrees C led to an increase in the frequency of transients. Furthermore, in T. riederi, large transients occurred only at the higher temperature. The frequency of spontaneous contractions of the tentacles of T. riederi was also temperature-dependent. Increasing the temperature over the range 5-26 degrees C led to a concomitant increase in contraction frequency and a decrease in mean tentacle length. The possible mechanisms of spontaneous Ca2+ transient generation and their role in the control of contraction are discussed.

Characterization of gastrin-releasing peptide receptor expressed in Sf9 insect cells by baculovirus

Whereas baculovirus expression systems have been extensively used for high-level expression of steroid receptors and receptors coupled to adenylate cyclase, there are few studies on peptide receptors coupled to phospholipase C (PLC). In the present study we have expressed the murine gastrin-releasing peptide receptor (mGRP-R) in Sf9 cells using a recombinant baculovirus and characterized it structurally and functionally. mGRP-R was detectible 12 h post infection with recombinant baculovirus carrying mGRP-R cDNA and became maximal at 60 h post infection (Bmax = 6 pmol/mg protein), which is a 4-60-fold greater density than is found in native tissues. The mGRP-R in Sf9 cells assessed by affinity labeling or immunoblotting was smaller than that in native tissues (M(r) = 51 kD vs 82 kD), and the difference was due to the extent of glycosylation. In Sf9 cells the mGRP-R had at least two of the four potential extracellular glycosylation sites glycosylated, whereas in the native receptor all four were approximately equally glycosylated. In Sf9 cells the glycosylation was entirely biantennary complex, in contrast to the native mGRP-R, where it was entirely tri- and tetraantennary complex N-linked oligosaccharides. Affinity labeling studies revealed a band with an apparent molecular mass about 40 kDa higher than the 51-kDa mGRP-R band. The intensity of this band correlated with the extent of functional G protein coupling, suggesting that it may represent an mGRP-R-G protein complex. In binding studies the affinity of the mGRP-r in Sf9 cells for the agonists bombesin (Bn), GRP, and neuromedin B (NMB) varied differently with infection time: with Bn the affinity decreased 3-fold with longer infection times, with GRP it remained unchanged, and with NMB it decreased 10-fold. GPP(NH)p inhibited binding of either [125I]Tyr4Bn or [125I]GRP at 24 h post infection, but not at 96 h post infection. Agonists activated PLC, increasing both [3H]IP and [Ca2+]i; however, the efficacy of each agonist decreased with infection time. These results demonstrate that by the use of recombinant baculovirus infected Sf9 cells the PLC-linked receptor mGRP-R can be expressed in amounts significantly greater than those in native tissues. The mGRP-R expressed in these Sf9 cells is incompletely glycosylated and has less complex N-linked oligosaccharide chains, yet it is fully coupled to G proteins and activates phospholipase C, similar to the native receptor, if short infection times are used.(ABSTRACT TRUNCATED AT 400 WORDS)

Multidisciplinary rehabilitation versus medical care: a meta-analysis

Research studies in physical medicine have not demonstrated the effectiveness of inpatient rehabilitation services, primarily due to differences in methodological approaches which have led to inconsistent findings. Because of differing inclusion and outcome criteria, even meta-analyses have been inconclusive. To address this problem, research literature comparing the clinical effectiveness of rehabilitation programs with medical care was evaluated for three uniformly available outcome criteria: survival; functional ability; and discharge location. Published trials were obtained from citations in Index Medicus (Medicine) and Nursing and Allied Health Abstracts covering the recent 20 year period from 1974 to 1994. We used meta-analyses to test the hypotheses that specialized rehabilitative care (vs conventional medical care) improves health outcomes. Results of our meta-analyses indicated that rehabilitation services were significantly associated with better rates of survival and improved function during hospital stay (P < 0.01), but significance was not observed at follow-up. Also, rehabilitation patients returned to their homes and remained there more frequently than controls (P < 0.001). We concluded that patients who participate in inpatient rehabilitation programs function better at hospital discharge, have a better chance of short term survival, and return home more frequently than non-participants. However, long term survival and function were the same for experimental and control subjects. The sustaining benefit of returning home may suffice to justify the provision of inpatient rehabilitation. However, the lack of other long term benefits suggests that services may need to be continued at home or in subacute care settings to optimize their effectiveness.(ABSTRACT TRUNCATED AT 250 WORDS)