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Biomedical subjects

V Riley

Publications and source records attributed to V Riley.

At least 19 recordsLinked to original sources
PubMed2002

Semen production in adolescent cancer patients.

BACKGROUND: The influence of an accompanying person (parent, guardian or nurse) on the ability of an adolescent (post-pubescent, <20 years of age) to produce a semen sample for cryopreservation, is undetermined, as is the potential for use of urine samples to retrieve sperm in those adolescents that are unable to produce a semen sample. METHODS: The records from 1991-2000 inclusive were reviewed to derive those adolescent patients who were unable to produce semen for cryopreservation prior to undergoing treatment for a malignant condition. RESULTS: During the study period 238 adolescents attended our unit of whom 205 (86.1%) banked semen ('producers'). The remaining 33 adolescents (13.9%) were initially unable to produce a sample ('non-producers'), four of these provided a urine specimen for analysis (12.1%) and of these one had sufficient sperm for cryopreservation. Of the 'accompanied' patients 29.7% (19/64) were non-producers while in the 'unaccompanied' patients only 8.0% (14/174) were non-producers (chi(2) = 16.58, P < 0.001). The relative risk (RR) of not producing a semen sample for the accompanied group of patients was greater than that for the unaccompanied group (RR = 3.689, 95% confidence interval: 2.0-6.9). One patient returning alone successfully provided a semen sample for storage. CONCLUSION: Units should consider the effect of the presence of an accompanying person when an adolescent is unable to produce a semen sample and should consider requesting urine to retrieve sperm.

Adolescent↗
PubMed2000

Exploring the sexual histories of older GUM clinic attenders.

Little is known either of the factors motivating clinic attendance in later life, or the sexual health histories of older clinic attenders. A self-administered questionnaire study linked to patient note data aiming to explore these issues was undertaken within 3 genitourinary medicine (GUM) clinics in the Trent region. Participants comprised 224 individuals aged 50 years and older attending the 3 clinics during the study period. The majority of study participants were attending the clinic with a suspected sexually transmitted infection (STI) (n = 145, 64.7%) and approximately half (n=119, 53.1%) were first-time GUM clinic attenders. Data available for participants recruited from the Sheffield clinic indicated that, although the majority of participants reported having had only one sexual partner during the last 12 months, a significant minority reported considerably higher numbers of partners, including those classed 'higher risk' for STI acquisition. These data indicate that older people engage in behaviours that place them at risk of STI acquisition and many attend GUM clinics for the first time in later life.

Age Factors↗
PubMed1999

A rational algorithm for duplex scan surveillance after carotid endarterectomy.

PURPOSE: This study was undertaken to determine the appropriate timing and frequency of duplex ultrasound scanning after carotid endarterectomy (CEA) for the detection of high-grade stenosis caused by recurrent carotid stenosis or contralateral atherosclerotic disease progression. METHODS: In 221 patients who underwent 242 CEAs, duplex scanning was performed before, during, and after operation (in 3-month to 6-month intervals). High-grade internal carotid artery (ICA) stenosis (peak systolic velocity, >300 cm/s; diastolic velocity, >125 cm/s; ICA/common carotid artery ratio, >4) prompted the recommendation for repair. An average of four postoperative scanning procedures was performed during a mean follow-up period of 27.4 months. RESULTS: Intraoperative duplex scan results prompted the immediate revision of 12 repairs (4.9%), and one perioperative stroke (<1%) occurred. Six CEAs (2.7%) had asymptomatic recurrent stenosis (>50% diameter-reduction [DR]; systolic velocity, >125 cm/s) develop. Only one of six patients had >75% DR stenosis develop and underwent reoperation (<1% yield for CEA surveillance). The yield of surveillance of the unoperated ICA was higher (P =.003), and 12% of unoperated sides had progressive stenosis (n = 21) or occlusion (n = 3) develop, which led to seven CEAs for high-grade stenosis. Disease progression to >75% DR stenosis was five times as frequent (P =.002) in patients with >50% DR stenosis initially. All patients but one who required contralateral endarterectomy for disease progression had >50% ICA stenosis when first seen. During the follow-up period, no disabling strokes ipsilateral to an operated carotid artery occurred, but three strokes occurred in the hemisphere of the contralateral unoperated ICA. CONCLUSION: The yield of duplex scan surveillance after CEA was low. Only 13 patients (5.9%) had severe disease develop to warrant additional intervention. Progression of contralateral disease rather than restenosis was the most common abnormality that was identified. Duplex scanning at 1-year to 2-year intervals after CEA is adequate when a technically precise repair is achieved and minimal contralateral disease (<50% DR) is present. A policy of duplex scan surveillance and reoperation for high-grade stenosis was associated with a 1.6% incidence rate of disabling stroke during the follow-up period.

Adult↗
PubMed1999

Delay in symptom presentation among a sample of older GUM clinic attenders.

Prior research undertaken with predominantly youthful populations has established that delay between symptom recognition and health-care presentation is a common feature of sexually transmitted infection (STI) related illness behaviour. However, it is not known whether similar behaviours are exhibited by older populations with genitourinary symptoms. The present analyses therefore aim to clarify this issue by focusing upon (1) extent of delay behaviour, (2) reasons for delay behaviour and (3) variables predicting delay behaviour among a sample of genitourinary medicine (GUM) clinic attenders aged over 50 years. A self-administered questionnaire study linked to patient note data was undertaken within 3 GUM clinics in the Trent region between January 1997 and March 1998 (Sheffield, Nottingham and Leicester). Of 121 symptomatic older attenders with suspected STI, 43.8% (n=53) waited over 2 weeks between symptom recognition and clinic attendance. Reasons given for delay included wanting to 'wait and see' if symptoms improved and being embarrassed or afraid to attend clinic. A logistic regression analysis identified that delay behaviour was predicted by history of HIV testing. Comparisons with previous research undertaken in this field indicate that levels of delay behaviour reported by this older sample are higher than those exhibited by youthful populations with genitourinary symptoms. This finding has significant implications for health-care professionals working both within a GUM setting, and with older people, especially when viewed in the context of an ageing population.

Aged↗
PubMed1997

Isolated microscopic haematuria in the genitourinary clinic: the value of renal biopsy.

Isolated microscopic haematuria is a common finding in the genitourinary clinic. The conventional approach to investigation includes urological referral for cystourethroscopy if renal imaging is normal. However the diagnostic yield is very low; in particular urothelial malignancy at age < 40 years is rare. Glomerular disease is increasingly recognized as a common cause of microscopic haematuria. In this study 50 patients with persistent microscopic haematuria detected at a genitourinary clinic underwent renal biopsy. Twelve (24%) had an abnormal biopsy--IgA nephropathy 6 (12%), thin membrane nephropathy 3 (6%), other glomerulonephritis 3 (6%). In 7 others no abnormality was found but information was incomplete as electron microscopy was unavailable. It is important to establish these diagnoses since some patients will develop progressive renal disease. In this clinical setting renal biopsy will give diagnostic and prognostic information, protects from repeated urological investigation, and allows reassurance if renal histology is normal. Renal biopsy is recommended for patients age < 40 years with persistent microscopic haematuria. An algorithm for the investigation of microscopic haematuria is presented.

Adult↗
PubMed1991

Quantification of Candida albicans morphology in vaginal smears.

The morphology index (Mi) of Candida albicans cells was determined by microscopic image analysis in vaginal smears from 26 patients. The morphology of the cells typically showed a broad distribution of forms, but the mean Mi was greater than 2.0 in 23/26 instances, indicating a preponderance of pseudohyphal and hyphal forms. No association could be found between Mi and the clinical assessment of signs or symptoms of Candida infection. Comparison of these 26 patients with 43 others who had Candida-positive vaginal smears but with fewer than 15 fungal cells in the smear revealed significantly lower scores for vulvovaginal symptoms among the latter.

Candida albicans↗
PubMed1981

Psychoneuroendocrine influences on immunocompetence and neoplasia.

Emotional, psychosocial, or anxiety-stimulated stress produces increased plasma concentrations of adrenal corticoids and other hormones though well-known neuroendocrine pathways. A direct consequence of these increased corticoid concentrations is injury to elements of the immunological apparatus, which may leve the subject vulnerable to the action of latent oncogenic viruses, newly transformed cancer cells, or other incipient pathological processes that are normally held in check by an intact immunological apparatus. This article describes studies that examine the adverse effects of increased plasma concentrations of adrenal corticoids on the thymus and thymus-dependent T cells, inasmuch as these elements constitute a major defense system against various neoplastic processes and other pathologies. The studies demonstrate that anxiety-stress can be quantitatively induced and the consequences measured through specific biochemical and cellular parameters, providing that authentic quiescent baselines of these conditions are obtained in the experimental animals by the use of low-stress protective housing and handling techniques.

Animals↗
PubMed1981

Hemodialysis of amino acids: basic studies in vitro.

Amino acids were efficiently removed in vitro from blood plasma, or its saline equivalent, with a standard hemodialyzer (artificial kidney). The rate of dialysis, or clearance, of the smaller amino acids approached that of urea, while the larger amino acids were removed at a slightly slower rate. A generalized inverse correlation was found between amino acid molecular weights and their clearance rates. By increasing the standard "blood" flow rate and/or the dialysate flow rate, the efficiency of the artificial kidney in removing amino acids from simulated blood was significantly increased. In the absence of endogenous influx, hemodialysis is an effective means for removing the entire spectrum of amino acids from circulating blood or its saline equivalent. These findings have provocative implications for experimental therapy based upon nutritional deprivations involving amino acids or other vital circulating biochemical components that may be differentially required by normal and cancer cells.

Amino Acids↗
PubMed1981

Concentrations of free amino acids and other blood components in a lymphoma patient during intensive hemodialysis.

l-Asparaginase is used as a therapeutic enzyme to selectively destroy asparagine-dependent cancer cells. This study explores alternate means for depriving cancer tissues of l-asparagine and other specific amino acids or vital substrates required by normal and cancer cells. Hemodialysis, employing an artificial kidney, was used to remove free amino acids from the blood of a patient with lymphoblastic lymphosarcoma. Approximately 1200 mg, the equivalent of the patient's total amino acid pool, was removed every 100 minutes while the patient was on the artificial kidney. Despite this impressive clearance capacity, the dialyzer was not able to completely overcome the endogenous amino acid influx of the patient. The combined data indicate that hemodialysis is theoretically capable of removing specific amino acids to a therapeutic level, but that the clearance efficiency of the artificial kidney must be significantly increased or the endogeneous amino acid influx must be effectively blocked before hemodialysis can be successfully applied to cancer patients. An unexpected finding was strikingly increased during dialysis but returned to the original levels when dialysis was temporarily discontinued. The presence of a nonprotein inhibiting factor capable of suppressing an increase in the peripheral malignant lymphocyte population could be an explanation. This postulated factor behaved during dialysis as though its molecular weight was relatively low, possibly less than 500.

Amino Acids↗
PubMed1981

Theoretical and practical considerations in the use of hemodialysis for the therapeutic removal of asparagine and other amino acids.

The endogenous asparagine influx in mice undergoing asparaginase therapy can be neutralized by asparaginase activity equivalent to less than one IU/ml of plasma, as determined with a new, highly sensitive micro assay for asparaginase. It appears feasible that an asparagine influx of this magnitude may be cleared from the blood plasma by hemodialysis employing an artificial kidney apparatus with a clearance capacity somewhat greater than that routinely employed by renal patients. Application of this method for removing asparagine or other amino acids from the blood as an approach to cancer therapy ultimately depends upon the specific amino acid influx rates of the subject and upon the ability of the dialyzer to deplete the free amino acids in the blood plasma at a sufficiently high rate to lower specific amino acid concentrations in malignant tissues, or in adjoining interstitial spaces, to therapeutic levels. Based upon the data available, hemodialysis has potential therapeutic application as a means to control the removal of various free amino acids or other metabolic substrates from blood plasma.

Amino Acids↗
PubMed1978

Increased tyrosine phenol-lyase activity in mice following pyridoxal phosphate administration.

A limiting factor in the depletion of plasma tyrosine following tyrosine phenol-lyase injection into normal mice was found to be the availability of an essential cofactor, pyridoxal phosphate. Because of the extremely short half-life of this cofactor, adequate elevation of circulating cofactor levels for prolonged periods by injection of a pyridoxal phosphate solution was not practical. Similarly, long-term diets enriched with pyridoxine and pyridoxal phosphate did not significantly improve the efficiency of the injected holoenzyme. A repository dosage form was devised that consisted of an s.c. implant of pyridoxal phosphate suspended in a spermaceti and peanut oil mixture. Under these conditions a sustained increase in holoenzyme activity levels and a significant resulting decrease in plasma tyrosine levels were obtained.

Animals↗
PubMed1976

Breast cancer patients: substance in blood causing acceleration of erythrocyte sedimentation rate.

The frequency distribution curve of the erythrocyte sedimentation rates obtained from a population of 3523 normal females was compared with the distribution found in 544 patients with benign breast disease and that for 385 patients with carcinoma of the breast. No significant difference was found between the normal female population and patients with benign lesions of the breast. This was in contrast to the distorted distribution curve of erythrocyte sedimentation rates exhibited by the population of patients having malignant breast lesions. An unknown substance present in the blood plasma of the cancer patients appears to be responsible for the abnormal sedimentation rate phenomenon.

Blood Sedimentation↗
PubMed1976

Antibody-producing cells: virus-induced alteration of response to antigen.

Spleen antibody-forming cells of mice yield a 3- to 10-fold increase in their response to sheep erythrocyte antigen if they are acutely infected by lactate dehydrogenase-elevating virus. This early stimulation is replaced by a long-term inhibition of the antibody-forming cells as the viremia goes into its persisting chronic stage. These contrasting immunological phenomena are examined as contributing factors responsible for the enhancement by this virus of asparaginase (EC 3.5.1.1; L-asparagine amidolydrolase) therapy against leukemia in mice, and for the alteration of the susceptibility of mice to various neoplastic processes.

Acute Disease↗