Regulation of cell movement is mediated by stretch-activated calcium channels

Intracellular calcium regulates many of the molecular processes that are essential for cell movement. It is required for the production of actomyosin-based contractile forces, the regulation of the structure and dynamics of the actin cytoskeletons, and the formation and disassembly of cell-substratum adhesions. Calcium also serves as a second messenger in many biochemical signal-transduction pathways. However, despite the pivotal role of calcium in motile processes, it is not clear how calcium regulates overall cell movement. Here we show that transient increases in intracellular calcium, [Ca2+]i, during the locomotion of fish epithelial keratocytes, occur more frequently in cells that become temporarily 'stuck' to the substratum or when subjected to mechanical stretching. We find that calcium transients arise from the activation of stretch-activated calcium channels, which triggers an influx of extracellular calcium. In addition, the subsequent increase in [Ca2+]i is involved in detachment of the rear cell margin. Thus, we have defined a mechanism by which cells can detect and transduce mechanical forces into biochemical signals that can modulate locomotion.

Crystallization by settling in suspensions of hard spheres

We examine crystallization by settling for two different model hard-sphere suspensions. Sedimentation velocities, internal shock velocities, and crystal growth velocities are measured. Dynamic light scattering experiments measure volume fraction profiles in fluid phases, while Bragg scattering experiments determine volume fraction profiles in crystal phases. Centrifugation experiments determine the particle Péclet number above which samples will not crystallize. The sedimentation velocities, as a function of volume fraction, agree with other "hard-sphere" data. Remarkably, the value of the reduced crystal growth velocity (approximately 0.075) obtains for two orders of magnitude of the particle Péclet number. Kynch theory provides an adequate description of the data in the fluid phase, but is less adequate for volume fraction profiles in the crystal phase. The crystals in the dense sediment are compressed more along a vertical axis relative to the horizontal axis. Predicted Wilson-Frenkel crystal growth velocities, calculated using known hard-sphere equations of state and a short-time self-diffusion constant, rationalize the measured crystal growth velocities.

Developing laser-induced glaucoma in rabbits

PURPOSE

An animal mode of glaucoma is necessary for the study of its pathogenesis and treatment. The purpose of this study was to create open-angle glaucoma using a laser in rabbits.

METHODS

The trabecular meshwork of anaesthetized, adult, pigmented and albino rabbits was ablated internally using a diode laser via a gonioscopy lens, or externally through the limbus. In albino rabbits we used Chinese ink to pigment the angle and methylcellulose to open the iridocorneal angle. The eyes were examined weekly and histological assessment was performed.

RESULTS

The success rate of intra-ocular hypertension was low (15%) and a result of synechial angle closure. A narrow angle prevented access of the laser beam to the trabecular meshwork and promoted damage to the ciliary processes located on the posterior iris.

CONCLUSIONS

Due to the unique anatomy of the rabbit eye, laser-induced glaucoma is difficult to achieve. To create a successful model it is necessary to widen the iridocorneal angle, selectively damage the trabecular meshwork and reduce inflammation.

Clinical and economic impact of newer versus older antipsychotic medications in a community mental health center

This pilot study was conducted to compare both the clinical effectiveness and the treatment costs of newer (atypical) antipsychotic medications (clozapine and risperidone) with those of older (classic) neuroleptic medications (chlorpromazine and haloperidol) for psychosis in a community mental health care setting. The study used a retrospective, uncontrolled, open, nonrandomized, within-subjects design and relied on medical records as a data source for 37 clients. All clients received older antipsychotics for at least 1 year, newer antipsychotics for a transition period of 3 months, and the newer agents for at least an additional year. The newer antipsychotic medications were more effective and less costly (total cost of care, $3000 less per client per year [1997 dollars]) than the older medications. Effect-size estimates for the measured variables provide a guide for future research into the cost-effectiveness of these newer medications within the community mental health care setting. These findings can provide policy makers with guidance on treating people with major mental disorders in the most effective and efficient manner. Because of limited budgets, community mental health centers making the investment in newer, more expensive medications to improve client outcomes have to maintain the same or lower total cost of care. Results of the current study suggest that short-term investment in the newer medications by community mental health centers offers superior clinical effectiveness and lower long-term overall cost of care.

Survivors' perspectives on the impact of prostate cancer: implications for oncology nurses

Providing effective care for individuals with prostate cancer is an important issue for oncology nurses. However, the paucity of empirical work regarding the impact of prostate cancer presents a limitation in designing and implementing appropriate nursing interventions. This article presents the findings from a national survey of 621 Canadian men living with prostate cancer regarding the impact of their disease and the availability of support. The most frequently identified problems included sexual function, side effects, fear of dying, incontinence, anger and pain. Approximately one-third of the respondents experienced a lifestyle change, but relatively few indicated experiencing a negative impact from the changes they experienced. The majority of respondents indicated they had been informed accurately about their treatment, but dissatisfaction was expressed regarding lack of information about emotional reactions, alternative therapies, how to speak with other prostate cancer patients and the availability of counselling and self-help groups. Clearly these results have implications for oncology nurses.

Vascular surgical society of great britain and ireland: limb outcome following failed femoropopliteal polytetrafluoroethylene bypass for intermittent claudication

BACKGROUND: Femoropopliteal (FP) bypass using polytetrafluoroethylene (PTFE) is still considered by many surgeons to be a reasonable procedure for severe intermittent claudication (IC) without limb-threatening ischaemia. The consequences of FP graft failure were examined. METHODS: Over 8 years, 54 patients had 55 FP grafts (that subsequently occluded) inserted for severe IC (42 PTFE and 13 vein grafts) above (30) or below (25) the knee. There were no operative deaths. During the same interval a total of 191 FP grafts were placed, 100 of which were vein grafts. Patient demography and risk factor analysis was similar for both groups. RESULTS: Nineteen patients required amputation subsequent to a failed graft, all of these following PTFE grafts. Mean time to occlusion was 12.2 (range 0-79) months. For PTFE grafts, the mean(s. d.) ankle index rose from 0.51(0.14) to 0.95(0.15) after operation but fell to 0.25(0.15) after occlusion, confirming a highly significant deterioration from preoperative levels, which was not seen in vein graft occlusions. CONCLUSION: Long-term FP bypass patency rates with vein are superior to those obtained with PTFE. Failed PTFE grafts show a significant deterioration in pressure indices compared with preoperative values. FP grafts for IC carry an intrinsic risk of limb loss which is much greater when vein is not used (P < 0.001).

Cross-sectional study of gastric ulcers of the squamous mucosa in thoroughbred racehorses

Although gastric ulcers have been identified relatively frequently in racing Thoroughbreds, there have been no large scale studies to determine their effect on health and performance. Two hundred and two Thoroughbred horses in active race training were selected by the attending veterinarians for gastro-endoscopic examination. Images of the stomach mucosa were stored in a digitised format for subsequent evaluation. The number of ulcers and a score of severity were determined. Gastric ulceration of the squamous mucosa was identified in 82% of horses. Seventy-three (39%) horses displayed clinical signs consistent with gastric ulceration. Increasing Furr and Murray Score was associated with poor hair coat (P = 0.03), colic (P = 0.03), and increasing serum creatinine concentration (P = 0.029). There were no associations between haematology and serum biochemistry values (other than serum alkaline phosphatase concentration and serum creatinine concentration) and gastric ulceration. Our study confirmed the relatively high incidence of gastric ulceration in Thoroughbred horses involved in active race training. Gastric ulceration is a potential, but rare, cause of overt colic, but may produce more subtle detrimental effects on a horse's condition. It is concluded that the diagnosis of gastric ulceration should be based on an endoscopic examination of the stomach, although future studies are required to elucidate further the aetiology and clinical significance of gastric ulceration.

Recombinant interleukin 2 adjunctive therapy in multidrug-resistant tuberculosis

Multidrug-resistant tuberculosis patients respond poorly to antituberculosis therapy and therefore require new modalities of treatment to overcome the infection. Administration of low dose recombinant human interleukin 2 (rhuIL-2) in combination with chemotherapy to multidrug-resistant tuberculosis patients resulted in reduced or cleared sputum acid-fast bacilli in about 60% of the patients in association with enhanced activation of the immune system. Daily rhuIL-2 administration for 30 days induced increases in CD25+ and CD56+ cells in the blood. rhuIL-2 therapy also resulted in increased expression of gamma-interferon and IL-2 mRNA at the site of a delayed-type hypersensitivity (DTH) response to purified protein derivative of tuberculin. Differential display reverse transcriptase PCR revealed several genes expressed at the DTH skin test site that were up- or down-regulated during rhuIL-2 treatment. The differentially regulated genes included components of endocytic vacuoles, enzymes of the respiratory pathway and other regulators of cellular function. The physiological importance of the differential expression of these genes is under investigation to determine their roles in leukocyte activation and in the development of an antimycobacterial response.

Weighing risks and taking chances: adolescents' experiences of the regimen after renal transplantation

The purpose of this study, which used a descriptive qualitative design, was to describe adolescents' experiences of the treatment regimen that follows renal transplantation in order to gain a better understanding of their experience. Five adolescents each participated in one in-depth, semistructured interview. Participants were asked to speak about the requirements of the recommended regimen related to medications, blood pressure and fluid monitoring, and diet and activity restrictions. The interviews were analyzed using Giorgi's data analysis method. The following overarching theme was identified: Weighing risks and taking chances. The consequences of the regimen and adhering or nonadhering to it were evident in the physiological, social, and psychological domains. Following the initial period, the adolescents were more selective in their adherence to the regimen, based on their perceptions of the risks involved in modifying the regimen. The modifications made to the posttransplantation regimen, which at times placed the adolescents' health at risk, were influenced by how the regimen interfered with their daily routines, such as school, leisure activities, and peer reactions as well as changes in their self-concept and self-image.

Emergency department hemodialysis in a case of severe ethylene glycol poisoning

A 36-year-old man with a history of depression presented to the emergency department after ingesting approximately 3,000 mL of ethylene glycol antifreeze in a suicide attempt. The patient's ethylene glycol concentration, 1,889 mg/dL, was higher than any level previously documented in the medical literature. Although his course was complicated by nausea, emesis, lethargy, metabolic acidosis, and kidney failure, the patient survived without persistent kidney failure or other chronic problems. Sustained hemodialysis and ethanol infusion were instituted in the ED, on the basis of the patient's history, before laboratory confirmation of the ingestion was obtained.

Three perspectives on addiction

Three perspectives on addiction promulgated during the 1990s are reviewed, along with many earlier contributions to the understanding of addictive illness. It is suggested that these distinct yet overlapping formulations of the dynamics of addiction form a hierarchy for each patient suffering from an addiction. Assessment of a patient's ego strength, and of the relative importance of addictive behaviors in overall character structure, allows referral to various types of treatment, including psychoanalytic therapy. Case examples are presented, including material from the psychoanalysis of a woman addicted to heroin, methadone, cocaine, amphetamines, nicotine, alcohol, and shopping.

Blue-green algae toxicosis in cattle

Twenty-four of 175 heifers died after ingesting water from a stock pond containing blue-green algae (genus Microcystis) in southern Colorado. Affected cattle were found dead or had signs of nervousness, and were recumbent, weak, anorectic, and hypersensitive to noise when first examined. All cattle died within 3 days after the onset of signs. At necropsy, the rumen contained blue-green algae, and the liver was larger than normal, friable, and dark red. The most important histologic lesion was hepatocyte degeneration and necrosis. Intraperitoneal administration of lyophilized cell material from the bloom caused hepatic necrosis and death in mice, and water from the pond had clumps of cells surrounded by a clear calyx, consistent with the appearance of organisms of the genus Microcystis. Samples of pond water were examined by means of high-pressure liquid chromatography; microcystin-LR, one of the hepatotoxins produced by Microcystis spp, was found. Chromatography may be useful in the diagnosis of blue-green algae toxicosis.

Chronically mentally ill individuals re-entering the community after hospitalization

The purpose of this phenomenological study was to increase the understanding of the experiences of chronically mentally ill individuals who are re-entering the community after hospitalization. Ten individuals from an acute care psychiatric hospital who had had two or more admissions within a 12-month period were interviewed, shortly before discharge and subsequently between two and four times while in the community. Three interrelated themes emerged. First, at the time of discharge, the optimism of the participants about returning home was tempered by a realistic recognition of their problems. As time passed, their problems seemed to become their preoccupying focus and optimism faded. Second, for most of the participants, relationships with others, positive, negative or both, played an important role in their return to home and community. Third, participants who experienced more positive social relationships also described individual achievements and community involvement. The re-entry process was not a smooth transition for these individuals.

Medical reference databases used by Army primary care physicians in field environments

A cross-sectional survey of U.S. Army primary care physicians was done to answer two questions: (1) which medical reference materials are Army primary care physicians currently using when deployed to a field environment? and (2) what would they like to have for medical reference in a field environment? Of 740 surveys delivered to their intended recipients, 445 (60%) were returned. Currently, 96% of primary care physicians use books, 37% use journals, and 11% use computer software in their medical reference database. Of those now using books, 72% were satisfied with them, compared with 61% of those using journals and 45% of those using software. The most common book used was the Merck Manual. The most important characteristics desired in a field medical database were broad coverage, ease of use, and light weight. The majority of respondents believe that a good medial reference database is important but that current medical databases limit the quality of the medicine they practice in the field.

Barriers to seeking care following school vision screening in Rochester, Minnesota

School vision screening provides an effective way to identify children who require vision therapy, usually glasses. To benefit from screening, children with abnormal screening test results must receive follow-up eye care, but care may be delayed for months or years. This project used community focus groups in Rochester, Minn., to identify barriers that may delay seeking professional care following school vision screening. Major barriers identified included lack of community awareness about the frequency and potential effect of refractive errors in children, a parental perception of inadequate communication between schools and the parents and community, high cost of corrective lenses, limited availability of convenient eye care appointments, and adolescents reluctance to wear glasses. Program planners developed a community action plan to address the perceived barriers.