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Biomedical subjects

A Porter

Publications and source records attributed to A Porter.

At least 19 recordsLinked to original sources
PubMed2006

Outcome of post-prostatectomy radiotherapy in one institution.

We present a retrospective study to evaluate the outcome of postoperative radiotherapy for biochemical or clinical recurrent prostate cancer. Twenty-six patients (median age 60 years) underwent radiotherapy after radical prostatectomy between January 1997 and January 2004. Seven patients received adjuvant radiotherapy and 19 received salvage radiotherapy. The median prostate-specific antigen at diagnosis was 8.6 (0.9-89) and most (23 patients) presented with T(3)N(0) disease. The median follow up was 19.5 months (5-84 months). All patients received a dose of 61.2 Gy at 1.8 Gy per fraction, 20 initially receiving 45 Gy to the lesser pelvis. The median dose to the bladder, rectum and left femoral head were 55.6, 57.5 and 33.8 Gy, respectively. All patients were managed radiotherapeutically by the first author. Twenty-four patients are alive. Two patients have died, one from oesophageal cancer and the second from metastatic prostate cancer. Two other patients also developed metastatic disease. Four asymptomatic patients with a rising prostate-specific antigen are under observation. None of the 26 patients has developed a local recurrence. Seven patients have developed grade 1 late bowel effects and three a grade 2 late effect. Eight patients suffer from grade 1 late genitourinary effects and two from grade 2 effects. One patient developed impotence, whereas 23 patients were rendered impotent postoperatively. There were no grade 3/4 late effects. Postoperative radiotherapy is well tolerated and provides effective local control.

Aged↗
PubMed2005

Effect of carbonate substitution on the ultrastructural characteristics of hydroxyapatite implants.

Carbonate ion substitution has been shown to be beneficial for increasing the amount of in vivo osseointegration to hydroxyapatite (HA). Nevertheless, mechanisms by which carbonate ions increase in vivo bioactivity are not fully understood. Sintered granules of HA and carbonate-substituted hydroxyapatite (CHA) were implanted for 6 and 12 weeks in an ovine model. Samples containing the bone-implant interface were prepared for transmission electron microscopy (TEM) and TEM was used to compare the in vivo reactivity of sintered granules of HA and CHA. The current findings demonstrated that CHA (1.2 and 2.05 wt.%) is more soluble than pure HA in vivo. More dissolution was observed from the CHA, at the bone-implant interface and within the implant, when compared to pure HA. A less crystalline phase was formed between the 2.05 wt.% CHA and bone at 12 weeks in vivo. Bone surrounding both the pure HA and 1.2 wt.% CHA was relatively disorganised at 12 weeks. In comparison, bone surrounding the 2.05 wt.% CHA was considerably more organised and in many regions collagen fibrils were present. Despite increased quality of bone surrounding 2.05 wt.% CHA, compared to 1.2 wt.% CHA, the amount of dissolution from both materials was similar.

Animals↗
PubMed2002

Monoclonal antibodies reactive with secreted-excreted products from the amphids and the cuticle surface of Globodera pallida affect nematode movement and delay invasion of potato roots.

This paper describes Excreted-secreted proteins (ES) proteins that were immunolocalised in the cuticle, amphids and subventral glands of second stage juveniles of the two species of potato cyst nematodes (Globodera pallida and Globodera rostochiensis). Monoclonal antibodies reactive with these ES proteins were used in a bioassay to investigate their effect on nematode movement and on their ability to invade potato roots. Antibodies recognising the nematode cuticle surface and the amphids affected nematode movement and delayed nematode penetration of roots. These effects were temporary, since the nematodes were able to recover and infect potato roots. Movement of second stage juveniles treated with the antibodies was impaired for the first 30 min after inoculation: the juveniles remained close to the point of introduction and moved slowly and abnormally. They recovered normal movement after 1-2 h, possibly because the turnover rate of the secreted proteins meant that they were no longer blocked by the monoclonal antibodies. No effect was observed on second stage juveniles treated with an antibody reactive with secretions from the oesophageal glands. Nematodes treated with antibodies reactive with the nematode cuticle surface were notably more affected than those treated with other antibodies; nematodes failed to recover movement when in continuous contact with the antibodies. It is possible that the physical presence of the antibodies on the nematode surface affected their motility. Nematodes treated with antibodies reactive with secretions from the amphids were temporarily unable to move towards potato roots and their exploratory behaviour was greatly affected by the antibody treatment. Whether these antibodies were able to inhibit temporarily the function of the amphids or this effect was due to physical presence of the antibodies blocking the amphidial pore remains to be determined.

Animals↗
PubMed2001

SITA visual field testing in children.

PURPOSE: The Swedish Interactive Thresholding Algorithm (SITA) is a new testing strategy for the Humphrey perimeter. The standard SITA algorithm shortens test time in adults without increasing variability, but its usefulness for detecting field defects in children has not been investigated. METHODS: We evaluated 92 standard SITA 24-2 visual fields of children, most of whom had various types of optic neuropathies (pediatric idiopathic intracranial hypertension, homonymous defects, bitemporal defects, papilledema from brain tumors), and compared them with 49 full threshold 24-2 fields obtained in similar patients. We evaluated outcome measures of foveal threshold, mean defect, pattern standard deviation, false-negative and false-positive rates, and test time. Five children (9 eyes) had both SITA and full threshold testing (FTT). RESULTS: The SITA decreased test time by over 50% compared with FTT (12.6 +/- 3.0 minutes vs 6.6 +/- 1.6 minutes [P <.00001]). When patients with field defects were eliminated, the pattern standard deviation was lower with SITA than FTT (P <.002), indicating lower intratest variability of SITA in subjects with normal fields. No detectable difference was observed in the other outcome measures. Subjective analysis of gray-scale fields in patients who underwent testing with the use of both strategies showed marked similarities. CONCLUSIONS: SITA shortens test time significantly compared with FTT and does so without jeopardizing interpretability. SITA has less intratest variability than FTT and therefore should be better for detecting and following defects. Caution is advised when following a visual field defect unless the same strategy is used for each evaluation. Switching strategies in the absence of a stable field defect is not recommended.

Adolescent↗
PubMed2001

Advancing perspectives on prostate cancer: multihormonal influences in pathogenesis.

Nonandrogenic hormones are implicated in the growth and function of the prostate, which is itself an endocrine gland that synthesizes and secretes hormones and growth factors, including follicle-stimulating hormone (FSH) and prostatic inhibin peptide (PIP). Findings of increased FSH concentrations and receptor expression in diseased prostate tissue suggest a role for FSH in prostate cancer growth. Not only does PIP suppress circulating levels of FSH, but it responds to and modulates prostatic FSH, suggesting a close interlinkage of these compounds in controlling both healthy and diseased prostate cells. Other focuses of endocrinologic research include androgen receptors, vitamin D, growth factors (including insulin-like growth factors I and II), and retinoids. Issues such as optimal therapy timing, intermittent administration, and the adoption of a multihormonal approach to the management of prostate cancer remain to be resolved.

Follicle Stimulating Hormone↗
PubMed2000

Prognostic significance of mild mitral regurgitation by color Doppler echocardiography in acute myocardial infarction.

Mitral regurgitation (MR) complicating acute myocardial infarction (AMI) is associated with increased mortality. The prognostic significance of only mild MR detected by echocardiography in patients with AMI is unknown. This study assessed the long-term risk associated with mild MR detected by color Doppler echocardiography within the first 48 hours of admission in 417 consecutive patients with AMI. No MR was detected in 271 patients (65%), mild MR was seen in 121 patients (29%), and moderate or severe MR was noted in 25 patients (6%). One-year mortality rates were 4.8%, 12.4%, and 24%, respectively (p<0.001). Multivariate analysis revealed that mild MR was independently associated with increased 1-year mortality (p<0.05) after adjustment for age, gender, previous myocardial infarction, diabetes mellitus, systemic hypertension, Killip grade > or =2 on admission, and left ventricular ejection fraction < or =40%. The hazard ratio for 1-year mortality was 2.31 (95% confidence interval 1.03 to 5.20) for mild MR and 2.85 (95% confidence interval 0.95 to 8.51) for moderate or severe MR. Thus, mild MR detected by color Doppler echocardiography within the first 2 days of admission in patients with AMI is a significant independent risk predictor for 1-year all-cause mortality.

Adult↗
PubMed2000

Microparticle-containing oncotic solutions augment in-vitro clot disruption by ultrasound.

Echocardiographic contrast agents enhance blood clot disruption by ultrasound. It has been suggested that the microbubbles add nuclei for the enhancement of cavitation by ultrasound. However, microbubbles are rapidly destroyed by the ultrasound energy. We assessed whether non-gas filled colloidal solutions (hyperoncotic medium molecular hydroxyethyl starch and degraded gelatin polypeptides) will facilitate clot disruption by ultrasound. In two separate experiments human blood clots, 200-400 mg in weight, were weighed and then immersed for 15 seconds in 10 ml normal saline solution containing 0%, 0.1%, 1%, 2%, and 5% of hyperoncotic medium molecular hydroxyethyl starch or 0%, 0.035%, 0.175%, 0.35%, and 0.7% degraded gelatin polypeptides. Clots were randomized to 10 seconds 20 kHz ultrasound or immersion without ultrasound. After treatment, the clots were reweighed, and the percent difference in weight was calculated. Non-gas filled microparticle-containing solutions such as hyperoncotic medium molecular hydroxyethyl starch and degraded gelatin polypeptides significantly augmented blood clot disruption by ultrasound. The effect is dependent on the colloidal solution concentration with maximal effect achieved with 1% hyperoncotic medium molecular hydroxyethyl starch and 0.35% degraded gelatin polypeptides.

Blood Coagulation↗
PubMed2000

Immunofluorometric assay of human kallikrein 6 (zyme/protease M/neurosin) and preliminary clinical applications.

BACKGROUND: The human kallikrein gene family has contributed the best prostatic biomarkers currently available, including prostate-specific antigen (PSA) and human glandular kallikrein 2 (hK2). Recently, new members of the human kallikrein gene family have been identified. One new member is the KLK6 gene, encoding for human kallikrein 6 (hK6), which is also known as zyme/protease M/neurosin. In this paper, we describe development of antibodies and a sensitive immunofluorometric procedure for hK6 protein. METHODS: Recombinant hK6 protein was used as immunogen to develop polyclonal antibodies in rabbits and mice. These antibodies were used to develop a sandwich-type time-resolved immunofluorometric procedure for hK6. RESULTS: The newly developed hK6 immunofluorometric assay has a detection limit of 0.5 microg/L and upper concentration range of 200 microg/L. The assay is highly specific (no detectable cross-reactivity from PSA and hK2) and was used to quantify hK6 protein in various biologic fluids. Highest concentrations of hK6 were found in milk of lactating women, cerebral spinal fluid, nipple aspirate fluid, and breast cyst fluid. hK6 was also detected in male and female serum, in the majority of seminal plasmas and in a small fraction of amniotic fluids and breast tumor cytosols. hK6 was not detectable in urine. Chromatographic studies indicated that hK6 is present in these biologic fluids in its free, 30-kDa form. CONCLUSIONS: This is the first reported sensitive immunofluorometric procedure for quantifying hK6 protein. hK6 is a secreted proteolytic enzyme that is found at high levels in cerebrospinal fluid and all breast secretions. This assay will facilitate further studies to examine the possible application of hK6 in diagnostics, including cancer and neurodegenerative disorders.

Amniotic Fluid↗
PubMed2000

Thrombolysis is an effective and safe therapy in stuck bileaflet mitral valves in the absence of high-risk thrombi.

OBJECTIVES: We sought to evaluate the effectiveness and safety of thrombolytic therapy in stuck mitral bileaflet heart valves in the absence of high-risk thrombi. BACKGROUND: Current recommendations for the thrombolytic treatment of stuck prosthetic mitral valves are partially based on older valve models and inclusion of patients in whom high-risk thrombi were either ignored or not sought for. The feasibility and safety of thrombolysis in bileaflet models may be affected by the predilection of thrombi to catch the leaflet hinge. METHODS: We studied 12 consecutive patients (men/women = 5/7, age 58.8 +/- 14.9 years) who experienced one or more episodes of stuck bileaflet mitral valve over a 33-month period and received thrombolytic therapy with streptokinase, urokinase or tissue-type plasminogen activator. Transesophageal echocardiography was performed in all patients. Patients with mobile or large (>5 mm) thrombi were excluded. Functional class at initial episode was I-II in 4 patients (33.3%) and III-IV in 8 patients (66.6%). RESULTS: Patients receiving thrombolytic therapy achieved an overall 83.3% freedom from a repeat operation or major complications (95% confidence interval 51.6-97.9%). Minor bleeding occurred in three patients (25%) and allergic reaction in one (8.3%). Transient vague neurologic complaints, without subjective findings, occurred in four patients (33.3%). Three patients had one or more relapses within 5.2 +/- 3.1 months from the previous episode, and readministration of thrombolytics was successful. CONCLUSIONS: In clinically stable patients with stuck bileaflet mitral valves and no high-risk thrombi, thrombolysis is highly successful and safe, both in the primary episode and in recurrence. The best thrombolytic regimen is yet to be established.

Adult↗
PubMed2000

The effect of aortic valve replacement on left ventricular mass assessed by echocardiography.

AIMS: The aim of the study was to investigate whether aortic valve replacement (AVR) has different effects on the left ventricular mass (LVM) in patients with different types of aortic valve disease, i.e. aortic stenosis (AS), aortic regurgitation (AR), or combined disease. METHODS AND RESULTS: We studied 100 patients with AS; (n=57), AR; (n=22), and combined disease; (n=21). Each patient was evaluated before and up to 8.7 years (mean follow-up period 1.42 +/- 1.65 years) after operation by transthoracic echocardiography. LVM was calculated based on echocardiographic parameters. Following AVR, the LVM for the entire group decreased from 373 +/- 145 g to 280 +/- 102 g (P=0.0001). The AS subgroup lost 13.7 +/- 30.7% from the preoperative LVM, compared to 28.8 +/- 24.8% in the AR subgroup (P<0.05) and 23.1 +/- 33.1% in the combined subgroup. The preoperative LVM was higher among patients with AR vs. AS patients (501 +/- 173 g vs. 319 +/- 100 g respectively, P<0.05). The decrease in LVM was significantly higher in patients with preoperative AR compared to AS patients (165 +/- 150 g vs. 58 +/- 96 g, respectively, P<0.05). However, the postoperative LVM remained higher among the former. The only preoperative parameter (of the LVM formula) that was different between AR and AS patients was the left ventricular end diastolic diameter (68 +/- 11 mm vs. 51 +/- 7 mm, respectively, P<0.05). No significant differences were found in wall thickness among the groups studied. Univariate analysis showed that gender (male), type of aortic valve disease (AR vs. AS), and larger prosthetic valve diameter correlated significantly with greater decrease in postoperative LVM. In multivariate analysis comparing the above variables between AS and AR subgroups, only the patient's gender (i.e. male) was identified as an independent predictor of LVM regression. CONCLUSION: Patients with AR have a greater decline in LVM compared with patients with AS following AVR. The postoperative decline in LVM is higher among males and those with larger prosthetic valve diameter.

Aged↗
PubMed2000

Correlation between electrocardiographic subtypes of anterior myocardial infarction and regional abnormalities of wall motion.

BACKGROUND: Examination of the electrocardiogram is the most widely used means for diagnosis and early stratification of risk of acute myocardial infarction (AMI). The classical classification of the subtypes of anterior AMI is based on results of studies comparing the electrocardiograms recorded at various stages, mostly in the subacute or chronic stage of AMI, with autopsy findings. Reports regarding the correlation between electrocardiographic findings in the acute phase and regional abnormality of wall motion (AWM) detected by echocardiographic evaluation are sparse. OBJECTIVE: To investigate the relationship between the electrocardiographic and two-dimensional echocardiographic findings regarding patients with their first anterior AMI. DESIGN AND METHODS: We studied 58 patients, 44 men and 14 women of mean age 61.5 +/- 14.6 years, with their first anterior AMI who had undergone two-dimensional echocardiographic evaluation within 48 h of admission. Deviation of ST-segment trace from baseline was measured manually 0.06 s after the J point for all leads on the admission electrocardiogram. ST-segment elevation in the various leads was correlated to the incidence of regional AWM detected by echocardiography. RESULTS: ST-segment elevations > or = 0.1 mV in V1 leads were found for 21 (36.2%) patients. Basal anterior, basal anteroseptal, and basal septal AWM were seen more often for patients with than they were for patients without ST-segment elevation in V1 (57 versus 16%, P=0.003; 43 versus 13.5%, P=0.03; 43 versus 11%, P=0.01 respectively). In contrast to ST-segment elevation in lead V1, the only statistically significant difference in prevalence in the presence of regional AWM between patients with (n = 48) and without (n = 10) ST-segment elevation > or = 0.2 mV in lead V2 was in the inferoapical region (87.5 versus 40%; P=0.003). ST-segment elevation > or = 0.1 mV in leads aVL and V5 was found for 11 (19%) and 23 (40%) patients, respectively. There was no correlation between either lateral or apical regional AWM and the presence of ST-segment elevation in the anterolateral leads except for mid-lateral AWM, which was more often detected for patients with than it was for patients without ST-segment elevation in aVL leads (36.3 versus 6.4%, P=0.026). CONCLUSIONS: ST-segment elevation in lead V1 during the acute phase of anterior AMI is associated with a high incidence of regional AWM in the basal anterior, anteroseptal, and anterior regions, whereas ST-segment elevation in lead V2 is more often associated with AWM in the inferoapical region. ST-segment elevation in aVL leads is related to mid-lateral regional AWM.

Echocardiography↗