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Biomedical subjects

S L Jackson

Publications and source records attributed to S L Jackson.

At least 19 recordsLinked to original sources
PubMed2006

Mucor rouxii ultrastructure: cyclic AMP and actin cytoskeleton.

A comparative analysis of the effect of two compounds, dibutyryl-cyclic-AMP (dbcAMP) and latrunculin B, on the morphology and ultrastructure of the dimorphic fungus Mucor rouxii under aerobic growth conditions is presented. dbcAMP acts through the sustained activation of protein kinase A, and latrunculin B through the disruption of the actin cytoskeleton. Upon addition of these compounds to the growth medium at any stage of the germination process, cells lost polarised growth and switched to isodiametric growth. The effect was reversible. The morphologies, visualised by light microscopy or scanning electron microscopy (SEM), were alike. A switch from a rough to a smooth surface was observed by SEM when cells were repolarised by removal of the added compound. Ultrastructural changes under both conditions, as observed by transmission electron microscopy, were similar, the main feature being the enlargement of the cell wall, with irregular depositions, and detachment from the cell membrane. dbcAMP-treated cells showed a decrease in the number of glycogen granules compared with control and latrunculin B-treated cells. F-actin staining with fluorescein isothiocyanate-phalloidin showed that both dbcAMP- and latrunculin B-treated cells displayed a much lower fluorescence than control cells, with only a few pale plaques. The results suggest that the sustained activation of protein kinase A, which impairs polarised growth, might exert its effect through a modification of actin cytoskeleton organisation, very probably also involving an integrinlike pathway, as judged by the cell wall detachment and loss of cell adhesiveness of the dbcAMP-treated isodiametric cells.

Actins↗
PubMed2005

Improving the outcomes of anticoagulation in rural Australia: an evaluation of pharmacist-assisted monitoring of warfarin therapy.

OBJECTIVE: The aim of this project was to assess whether rural pharmacist involvement in the management of patients receiving warfarin has the potential to lead to safer and more effective anticoagulation, and is valued and welcomed by patients and their general practitioners (GPs). METHODS: A convenience sample of rural pharmacists was trained in the use of the CoaguChek S International Normalized Ratio (INR) monitor and then conducted pharmacy-based testing for approximately 3 months. Two types of testing were performed in the pharmacy: (i) comparison testing was defined as pharmacy-based tests taken within 4 h of conventional laboratory testing or (ii) additional testing, which was a pharmacy-based test with no direct comparison laboratory test taken. Pharmacists, GPs and patients completed anonymous satisfaction surveys after the completion of the pharmacy-based testing. RESULTS: Pharmacists from 16 rural pharmacies were trained to use the CoaguChek S monitor. During the trial period, 518 INR tests were performed in the pharmacies on 137 different patients. A total of 120 tests were evaluated against results from laboratory testing. The pharmacy-based INR values were significantly correlated with the laboratory INR values (mean of 2.32+/-0.77 and 2.32+/-0.59 respectively; r=0.88, P<0.0001). A total of 398 additional pharmacy-based tests were conducted in the pharmacy and 8.5% of the additional tests resulted in a subsequent dosage change. The monitoring was well received by pharmacists, GPs and patients. CONCLUSIONS: The results of the trial were very positive. The CoaguChek S monitor in pharmacy-based testing performed accurately compared with conventional laboratory testing. Further research needs to be conducted on the impact of community pharmacy-conducted INR monitoring on patient care and outcomes.

Adult↗
PubMed2004

Accuracy, reproducibility and clinical utility of the CoaguChek S portable international normalized ratio monitor in an outpatient anticoagulation clinic.

The accuracy and reproducibility of the CoaguChek S, and its clinical agreement with conventional laboratory international normalized ratio (INR) determination, were evaluated in an outpatient anticoagulation clinic setting. Forty-three patients provided 248 paired INR measurements for analysis. The paired results were highly correlated (r = 0.90). The mean coefficient of variation for the CoaguChek S for a random sample of 21 patients with three repeated tests each, was 4%. Clinical applicability was also measured by discrepant INR values, as defined in the literature by expanded and narrow agreement, and by INR values resulting in a different clinical decision by a blinded haematology registrar. Expanded agreement and narrow agreement between the two INR values occurred 90 and 88% of the time, respectively. The stricter criteria set down by the clinician resulted in 73% of paired results producing the same dosage decision. The CoaguChek S displayed good correlation with laboratory determination of INR and compared relatively well with expanded and narrow clinical agreement criteria.

Ambulatory Care Facilities↗
PubMed2004

Improving the outcomes of anticoagulation: an evaluation of home follow-up of warfarin initiation.

OBJECTIVES: A number of studies have reported that the risk of bleeding associated with warfarin is highest early in the course of therapy. This study examined the effect of a programme focused on the transition of newly anticoagulated patients from hospital to the community. DESIGN: Open-label randomized controlled trial. SETTING: Home-based follow-up of patients discharged from acute care hospital in southern Tasmania, Australia. SUBJECTS: A total of 128 patients initiated on warfarin in hospital and subsequently discharged to general practitioner (GP) care were enrolled in the study. Sixty were randomized to home monitoring (HM) and 68 received usual care (UC). INTERVENTIONS: HM patients received a home-visit by the project pharmacist and point-of-care international normalized ratio (INR) testing on alternate days on 4 occasions, with the initial visit two days after discharge. The UC group was solely managed by the GP and only received a visit 8 days after discharge to determine anticoagulant control. RESULTS: At discharge, 42% of the HM group and 45% of the UC group had a therapeutic INR. At day 8, 67% of the HM patients had a therapeutic INR, compared with 42% of UC patients (P < 0.002). In addition, 26% of UC patients had a high INR, compared with only 4% of HM patients. Bleeding events were assessed 3 months after discharge and occurred in 15% of HM patients, compared with 36% of the UC group (P < 0.01). CONCLUSIONS: This programme improved the initiation of warfarin therapy and resulted in a significant decrease in haemorrhagic complications in the first 3 months of therapy.

Adult↗
PubMed2001

Gelatinous ascites: a cytohistologic study of pseudomyxoma peritonei in 67 patients.

BACKGROUND: Pseudomyxoma peritonei (PMP) is a rare condition characterized by gelatinous ascites. Although the histologic attributes of PMP have been well studied, the cytologic features remain ill defined. METHODS: We reviewed the peritoneal washings (PW) in 67 patients with PMP to identify cytomorphologic features useful in classifying cases as either disseminated peritoneal adenomucinosis (DPAM) or peritoneal mucinous carcinomatosis (PMCA). Histologic specimens were correlated with the cytologic diagnoses. Correlation between cytologic diagnosis and patient outcome was investigated. RESULTS: Neoplastic epithelial cells were identified in 63 of 67 PW (94%). Concordance with the histologic diagnosis was obtained in 61 of 63 cases. Of these 36.5% were cytologically classified as DPAM with primary appendiceal neoplasms in 19 cases. Thirty-four of 63 cases (53.9%) were cytologically diagnosed as PMCA based on PW cytology. Most were of appendiceal or colonic origin. Four cases displayed cytologic features of both DPAM and PMCA. Two discordant cases each with a cytologic diagnosis of PMCA had an appendiceal adenoma. Acellular mucin alone was identified in the PW in four cases. Analysis of follow-up data revealed that cases diagnosed as DPAM had a better prognosis than those diagnosed as PMCA. CONCLUSIONS: Cytomorphologic features of epithelial cells in PW material can accurately categorize cases of PMP as either DPAM or PMCA. Furthermore, this categorization appears to have important prognostic implications.

Adenocarcinoma, Mucinous↗
PubMed2001

Outcomes in the management of atrial fibrillation: clinical trial results can apply in practice.

BACKGROUND: The benefits of antithrombotic therapy in chronic atrial fibrillation (AF) have been established in clinical trials, but there is a paucity of data on outcomes in practice. AIMS: The objective was to establish a large ongoing database of patients with non-valvular AF, to enable the accurate determination of clinical outcomes. METHODS: A retrospective review of the medical records for consecutive patients who had AF documented on electrocardiogram at the major teaching hospital in Tasmania between 1 January 1997 and 30 June 1999 was performed. An extensive range of demographic and clinical variables was recorded for all patients with chronic or paroxysmal non-valvular AF. RESULTS: The 505 patients (60% males) included in the database had a median age of 76 years. According to risk stratification criteria, 79% of the patients with previously diagnosed chronic or paroxysmal AF had a high risk of developing stroke at the time of admission to hospital care. However, only one-third (34%) of these patients were receiving warfarin (or warfarin plus aspirin), with almost one-quarter (24%) receiving no antithrombotic agent. The annual incidence of ischaemic strokes was 3.4% (1.5-6.4%; 95% CI) when taking warfarin, compared to 7.0% (5.2-9.4%) for patients not taking warfarin and 7.8% (5.4-11.1%) for patients taking aspirin. The annual incidence of bleeding complications in patients taking warfarin was 14.2% (10.0-19.5%) overall and 3.4% (1.5-6.4%) for major bleeds. In patients not taking warfarin, the overall annual incidence of bleeds was 8.4% (6.3-10.9%) and 3.9% (2.5-5.7%) for major bleeds. CONCLUSIONS: Warfarin is underused in patients with AF. In clinical practice, warfarin confers a similar stroke risk reduction to that observed in trials, with an increase in incidence of only minor bleeding complications. Aspirin did not appear to reduce the risk of stroke.

Adult↗
PubMed2000

Radiation-induced gastrointestinal stromal sarcoma of the esophagus.

Esophageal sarcoma is an uncommon tumor, sporadically reported in the literature. Radiation therapy is frequently employed in the treatment of carcinoma of the esophagus, and the increased risk of development of sarcoma arising in irradiated fields is well known. However, to our knowledge, the occurrence of radiation-associated sarcoma of the esophagus after radiation therapy for carcinoma of the esophagus has not been reported. We therefore report the case of a 43-year-old female who developed a gastrointestinal stroma sarcoma 9 years following radiation therapy for esophageal squamous cell carcinoma. The patient underwent resection of her gastrointestinal stromal sarcoma by transhiatal esophagectomy with cervical anastomosis and is doing well 18 months later. The increasing use of radiation therapy for esophageal carcinoma suggests that radiation-associated sarcoma of the esophagus may be seen more frequently in the future.

Adult↗
PubMed2000

Interfacing computerized biomechanical analysis in monitoring the motor development of children.

This research investigated the effectiveness of using kinematic analysis to monitor the motor development of children on three fundamental movement patterns. 12 children with specific motor delays were filmed before and after participation in the 2-hr. per week, 7-wk. program. The film was analyzed (60 frames per second) using a 2-dimensional analysis system. There were no significant differences when a Wilcoxon matched pairs signed-ranks test was applied to the galloping and skipping center of gravity and linear velocities of the ball data. Timing of the peak linear velocities of the upper body showed subjects increasingly exhibited the more advanced, sequential pattern and no longer exhibited the less advanced simultaneous pattern after the program. It was concluded the changes in timing were evidence of improvements in coordination.

Biomechanical Phenomena↗
PubMed1999

Traumatic subarachnoid haemorrhage: a 10-year case study and review.

Fourteen cases of traumatic subarachnoid haemorrhage (TSAH) from the years 1985-1995 are described. Two of these cases, one paediatric and one involving controlled substances, are considered separately. All 14 cases are then discussed together with the current literature with respect to: typical subject, the circumstances and aetiology of injury, time interval between injury and collapse; time of survival, the role of alcohol, the site of arterial rupture, and the methods recommended by other authors for the location of such an injury. We conclude that TSAH is a poorly understood cause of sudden death; fuller research is needed to clarify aetiology.

Adult↗
PubMed1999

Pelvic inflammatory disease in the postmenopausal woman.

OBJECTIVE: Review available literature on pelvic inflammatory disease in postmenopausal women. DESIGN: MEDLINE literature review from 1966 to 1999. RESULTS: Pelvic inflammatory disease is uncommon in postmenopausal women. It is polymicrobial, often is concurrent with tuboovarian abscess formation, and is often associated with other diagnoses. CONCLUSION: Postmenopausal women with pelvic inflammatory disease are best treated with inpatient parenteral antimicrobials and appropriate imaging studies. Failure to respond to antibiotics should yield a low threshold for surgery, and consideration of alternative diagnoses should be entertained.

Aged↗
PubMed1998

Fecal incontinence in women.

Pelvic floor disorders are common in women. Most gynecologists are well versed in the management of urinary incontinence and uterovaginal prolapse; however, knowledge of disorders involving the anorectum is often lacking. This review will discuss the issue of anorectal incontinence in women, attempt to provide a logical outline for evaluation and treatment, and offer potential methods of prevention.

Episiotomy↗
PubMed1997

Fecal incontinence in women with urinary incontinence and pelvic organ prolapse.

OBJECTIVE: To determine the prevalence of and factors associated with fecal incontinence in women with urinary incontinence or pelvic organ prolapse. METHODS: Study subjects were recruited prospectively, and all participants received questionnaires regarding bowel function and underwent a standardized history and physical examination. Fecal incontinence was defined as the involuntary loss of feces sufficient to be considered a problem by the patient. RESULTS: Forty-two subjects had fecal incontinence, an overall prevalence of 17%. One hundred seventy women had urinary incontinence, pelvic organ prolapse, or both, and 36 of these (21%) had fecal incontinence. One hundred (40%) women had urinary incontinence, of whom 31 also had fecal incontinence. Seventy women had isolated pelvic organ prolapse and five (7%) were incontinent of feces. Univariate analysis revealed that any degree of pelvic organ prolapse, increasing degrees of prolapse within each vaginal segment, urinary incontinence, advanced age, postmenopausal status, increased vaginal parity, prior hysterectomy, history of irritable bowel syndrome, and abnormal sphincter tone were associated significantly with fecal incontinence. Multiple logistic regression analysis indicated that only urinary incontinence (odds ratio [OR] 4.6, P < .001, 95% confidence interval [CI] 1.9, 11.2), abnormal anal sphincter tone (OR 2.3, P = .04, 95% CI 1.1, 5.1), and irritable bowel syndrome (OR 8.3, P = .002, 95% CI 2.1, 32.8) were associated with fecal incontinence. CONCLUSIONS: There is a high rate of fecal incontinence in women with urinary incontinence and pelvic organ prolapse. Clinicians providing health care to a similar group of women should inquire routinely and specifically about fecal incontinence.

Adult↗
PubMed1997

Sexually transmitted diseases in pregnancy.

Sexually transmitted diseases are common complications of pregnancy and may have significant maternal/fetal effects. Knowledge of the symptoms and physical examination features, methods of diagnosis, indications for screening, and appropriate treatment options are essential for obstetric/gynecologic health care providers.

Adult↗
PubMed1996

A transient rise in cytoplasmic free calcium is required to induce cytokinesis in zoosporangia of Phytophthora cinnamomi.

We studied the role of cytoplasmic free Ca2+ concentration ([Ca2+]i) in cytokinesis of zoosporangia of the water mold Phytophthora cinnamomi. In these cells cytokinesis is separated from nuclear division and can be triggered at precisely determined times by cold shock. Changes in [Ca2+]i were monitored by ratiometric fluorescence imaging of pressure microinjected Fura-2 dextran. Two increases in [Ca2+]i always occurred in sporangia that underwent cytokinesis in response to cold shock. Within the first minute of cold shock, [Ca2+]i rose rapidly and transiently to levels 25 to 131% higher than the resting level of 104 +/- 54 nM. By 10 min, [Ca2+]i had decreased and was near the initial resting level. The second increase in [Ca2+]i was gradual and prolonged, accompanying cell division. Near completion of cytokinesis, [Ca2+]i had risen to 231 +/- 165 nM. The initial brief rise in [Ca2+]i was absent in sporangia that did not undergo cleavage. Microinjection of the Ca2+ buffer 5,5'-dibromo-BAPTA before cold shock, blocked cytokinesis suggesting that the transient rise in [Ca2+]i may be necessary for induction. The subsequent gradual increase in [Ca2+]i may not be critical because microinjection of 5,5'-dibromo-BAPTA during cleavage plane development did not always perturb division.

Calcium↗
PubMed1993

Roles of calcium ions in hyphal tip growth.

A role for Ca2+ in the tip growth process of fungal hyphae and other eukaryotic walled cells has been widely explored, following the earlier indications of their importance by Jaffe, Steer, and their colleagues. Analysis of the literature on fungi, with selected comparison with other tip-growing plant cells, shows that the growth rate and morphology of hyphae are sensitive to factors which influence intracellular Ca2+. These factors include variations in extracellular Ca2+ concentrations, Ca2+ ionophores, inhibitors of Ca2+ transport, and calmodulin- and Ca(2+)-binding dyes and buffers introduced into the cytoplasm. The effects of these agents appear to be mediated by a tip-high gradient of cytoplasmic free Ca2+ which is obligatorily present in all critically examined growing tips. Most recent observations agree that the gradient is very steep, declining rapidly within 10 to 20 microns of the tip. This gradient seems to be generated by the combined effects of an influx of Ca2+, via plasma membrane, possibly stretch-activated, channels localized in the hyphal tip, and subapical expulsion or sequestration of these ions. Expulsion probably involves a plasma membrane Ca(2+)-ATPase, but it is not yet possible to differentiate among mitochondria, endoplasmic reticulum, or vacuoles as the dominant sites of sequestration. It is suggested that regulation of the Ca2+ gradient in turn modulates the properties of the actin-based component of the cytoskeleton, which then controls the extensibility, and, possibly, the synthesis of the hyphal apex. Regulatory feedback mechanisms intrinsic to this model of tip growth regulation are briefly discussed, together with suggestions for future experiments which are crucial to its further elucidation and establishment.

Actins↗
PubMed1993

Ion channel activity and tip growth: tip-localized stretch-activated channels generate an essential Ca2+ gradient in the oomycete Saprolegnia ferax.

The plasma membrane of tip-growing hyphae of the oomycete Saprolegnia ferax contains stretch-activated (SA) Ca(2+)-permeable and Ca(2+)-activated K+ ion channels. Patch clamp measurements on protoplasts derived from specific regions of hyphae demonstrated that SA channels were most abundant in the tip. Gadolinium (Gd3+) inhibited SA channel activity and stopped tip growth. The Ca(2+)-sensitive fluorochrome INDO 1 revealed a tip-high gradient of free cytoplasmic Ca2+ in growing hyphae. This gradient could be dissipated with the addition of Gd3+. The calcium gradient returned and growth resumed when Gd3+ was washed out. This implies a fundamental requirement for growth for Ca2+ influx through the SA channels. Ca(2+)-activated K+ channels were distributed evenly along the hyphae. These channels were inhibited by tetraethylammonium concentrations which caused a rapid but transient decrease in growth. We suggest that the SA channels at the apex act as feedback sensors, responding to membrane stretching at the tip. They are an obligate requirement for tip growth. The Ca(2+)-activated K+ channels may act to maintain turgor pressure, but are not obligatory for growth.

Calcium↗