Search PubMed⌕ Search

Biomedical subjects

J Lemon

Publications and source records attributed to J Lemon.

18 recordsLinked to original sources
PubMed2006

Studies of male reproduction in captive African wild dogs (Lycaon pictus).

Implementation of assisted breeding in the captive African wild dog is restricted by a current lack of knowledge on their reproductive physiology and the apparent difficulty of effectively manipulating the complex social dynamic of the pack in order to conduct reproductive procedures. In this study, we describe protocols for the safe and repeated capture and restraint of the African wild dog (n=7) as well as techniques for assessment of male reproductive function, semen collection and preservation. In a serendipitous finding, captive African wild dogs appeared to display significant seasonal change in male reproduction. Testicular volume and tone, spermatorrhea and the ability to collect semen by electroejaculation all increased significantly during late summer and then subsequently declined by early spring. While there were no detectable seasonal changes in testosterone concentration in the population as whole, the alpha-dominant male in both years of the study, had a highly elevated testosterone concentration compared to subordinate males. Semen collection by electroejaculation during the late summer was most effective in peri-pubertal males (15 months) when all seven electroejaculates were of adequate quality for cryopreservation. In the second breeding season (27 months), there were numerous changes in the pack hierarchy and electroejaculation was not as successful (3/7). The characteristics of electroejaculated semen collected in the breeding season are described for seven animals including the first descriptions and incidence of sperm abnormalities in the species. Semen (n=7) was frozen using a Tris-citrate fructose buffer and final egg yolk and glycerol concentration of 20% and 4%, respectively. Sperm were loaded into 0.25 mL straws, frozen in liquid nitrogen vapor and then thawed at 37 degrees C. Initial post-thaw survival of spermatozoa was encouraging (% motile: 31.8+/-5.8%; rate: 2.8+/-0.3; % intact plasma membranes: 33.4+/-5.3% and the % of damaged acrosomes: 4.4+/-1.5%) but following 2 h incubation at 37 degrees C, post-thaw survival declined markedly.

Animals↗
PubMed2000

Experience with Barton button and peristomal breathing valve attachments for hands-free tracheoesophageal speech.

BACKGROUND: Tracheostoma breathing valves permit hands-free tracheoesophageal (TE) speech production; however, few laryngectomees routinely use them because of problems with attachment. METHODS: We retrospectively reviewed the charts of 45 TE speakers to determine the success rate and factors associated with successful breathing valve use based on attachment. All patients attempted to use a tracheostoma breathing valve with either a standard or customized peristomal housing, or a standard or customized Barton button. Device selection was based on inspection of the patient's neck and peristomal contour. Six to eight consecutive hours of attachment defined success. RESULTS: Overall, 9% of subjects succeeded with any peristomal attachment as compared to 68% with either a standard (57%) or customized (85%) Barton button. Smooth stomal contour, a contiguous stomal lip, and correct button length were important for successful Barton button use. CONCLUSIONS: Standard or customized Barton buttons offer excellent alternatives to peristomal housing attachments for hands-free TE speech in select patients.

Equipment Design↗
PubMed1997

Acute effects of kava, alone or in combination with alcohol, on subjective measures of impairment and intoxication and on cognitive performance.

Kava (Piper methysticum) and alcohol were administered either separately or in combination to human subjects. Self-reports of their levels of impairment and intoxication were collected, and performance skills on a number of cognitive and visuomotor tests were determined, before and three times after consumption of the experimental drink. Kava alone had no effect on reported condition. In contrast, alcohol produced marked changes in each of the five subjective measures, all of which were in the direction of lowered ability. The combination of these two substances produced even larger negative changes on these measures. In the cognitive tests, kava produced a decrement in performance on Digit Symbol Coding. Alcohol produced a significant decrease in performance on a divided attention test, which was almost entirely on the peripheral, discontinuous component of the test. The combination of kava and alcohol produced an even greater decrease in performance on this test, and in the same component. The present findings suggest that kava alone has little effect on reported condition and cognitive performance, but appears to potentiate both perceived and measured impairment when combined with alcohol.

Journal Article↗
PubMed1997

Cognitive deficits in patients suffering from chronic fatigue syndrome, acute infective illness or depression.

BACKGROUND: Patients with chronic fatigue syndrome (CFS) report neuro-psychological symptoms as a characteristic feature. We sought to assess cognitive performance in patients with CFS, and compare cognitive performance and subjective workload experience of these patients with that of two disease comparison groups (non-melancholic depression and acute infection) and healthy controls. METHOD: A computerized performance battery employed to assess cognitive functioning included tests of continuous attention, response speed, performance accuracy and memory. Severity of mood disturbance and subjective fatigue were assessed by questionnaire. RESULTS: All patient groups demonstrated increased errors and slower reaction times, and gave higher workload ratings than healthy controls. Patients with CFS and non-melancholic depression had more severe deficits than patients with acute infection. All patient groups reported more severe mood disturbance and fatigue than healthy controls, but patients with CFS and those with acute infection reported less severe mood disturbance than patients with depression. CONCLUSIONS: As all patients demonstrated similar deficits in attention and response speed, it is possible that common pathophysiological processes are involved. The differences in severity of mood disturbance, however, suggest that the pathophysiological processes in patients with CFS and acute infection are not simply secondary to depressed mood.

Acute Disease↗
PubMed1993

Alcoholic hangover and performance: a review.

The study of alcoholic hangover is reviewed, with particular concern given to its effects upon skills performance. Different models of hangover, and the evidence gathered in their support, are surveyed. Several factors appear to contribute to hangover, and individuals may be differentially susceptible to these influences. The severity of hangover is affected by dose, coproducts of manufacture, and a number of psychological variables. Hangover is differentiated from post-intoxication effects on performance, and the results of a variety of studies on these effects are considered. Post-intoxication effects have been found in a variety of tasks, but no tasks have been consistently affected in a number of studies. This may reflect the fact that few studies have used the same tasks to assess performance. Proposed mechanisms of post-intoxication effects are considered, and the most consistent symptom accompanying impaired performance is found to be fatigue. This notion finds some support in electroencephalographic data collected during the period following intoxication.

Journal Article↗
PubMed1993

The use of a computer-assisted telephone interview technique in a general practice research study.

We describe the principles and practice of computer-assisted telephone interviewing, and its successful deployment in a general practice-based research study into the referral behaviour of general practitioners (GPs) in the Grampian region of Scotland. Participating GPs were interviewed concerning the acceptability of the method. It proved to be an efficient and acceptable method for collecting data from a large number of practitioners in this large geographical area. Our experience confirms that this efficient method of data collection could be much more widely utilized in primary care research.

Computers↗
PubMed1993

Clinical birthweight standards for a total population in the 1980s.

OBJECTIVE: To derive clinical standards for singleton birthweight in a population based on area of residence. DESIGN: Analysis of variables recorded in Aberdeen Maternity and Neonatal Databank, calculating for each birth a standardised birthweight score, taking account of determining factors. SUBJECTS: All singleton live births of 32 to 42 weeks gestation to Aberdeen City District residents from 1979 to 1983. RESULTS: Basic standards of birthweight are presented correcting for gestational age, sex of the baby and parity of the mother. Birthweight is not normally distributed and empirical data are presented rather than smoothed curves. Adjustment for maternal height is straightforward but adjustment for maternal weight must take account of the gestation at which the woman was weighed. A method of calculating the appropriate correction for height and weight is described in detail. CONCLUSION: Birthweight is not normally distributed at each week of gestation. Standardisation for parity, gestation and sex of the baby is essential, but adjustment for maternal size is complex.

Birth Weight↗
PubMed1993

Investigation of the "hangover" effects of an acute dose of alcohol on psychomotor performance.

Performance on some complex and difficult tasks has been shown to be negatively affected for some time after an acute dose of alcohol has been cleared from the system. However, Dauncey reported impairment of a relatively simple reaction time task 3 hr after a dose of alcohol, when the blood alcohol concentration was at or near 0. This impairment was positively related to the subject's drinking history. A replication using the same task found a linear dose/impairment relationship during intoxication. A second simple reaction time task and a vigilance task showed a trend toward impairment, but only a divided attention task was significantly affected during intoxication. There was no significant effect of dose on any of these tests during a "morning after" session. The results are discussed in relation to the differences in method between Dauncey and this study.

Adult↗
PubMed1992

Randomized study of peritonitis with conventional versus O-set techniques in continuous ambulatory peritoneal dialysis.

We performed a prospective randomized trial, comparing the incidence of peritonitis between a flush-disconnect (O-System, Baxter, Deerfield, IL) (OS) and a conventional (System II, Baxter) (CS) continuous ambulatory peritoneal dialysis (CAPD) method. Sixty consenting patients with no significant physical disabilities who commenced CAPD after May 1987 were entered and followed for a minimum of 12 months. Thirty were placed on the OS system and 30 were placed on CS. Age, gender, and time for training did not differ significantly. The period of observation for OS was 375 months; CS was observed for 430 months. OS patients experienced 28 episodes of peritonitis (13.4 months/patient/episode) compared with 88 (4.9 months/patient/episode) in CS (p less than 0.005). By 6 months, 32% of OS patients had had at least one episode of peritonitis, compared with 62% of CS patients; at 12 months, these figures rose to 48% for OS and 91% for CS (p less than 0.01) patients (Life Table Analysis). The median survival time to first peritonitis episode was 5.1 months in CS and 9.7 months in OS (p less than 0.01). Exit-site infections occurred in 14/30 (46%) of patients on OS and in 13/30 (43%) of CS patients. We conclude that the OS was associated with a significant reduction in the incidence of peritonitis.

Catheters, Indwelling↗
PubMed1990

Growth patterns in preterm and term twin deliveries.

Preterm deliveries in singleton pregnancies have been shown to be associated with decreased rate of growth in utero. A total of 113 sets of twins were scanned serially at fortnightly intervals to establish fetal growth. There was no significant difference in the growth pattern in twins delivered before 37 weeks compared to those delivered after this time.

Body Constitution↗
PubMed1989

Mode of delivery and future fertility.

A cohort of 22,948 women from a stable homogeneous population who gave birth for the first time between 1964 and 1983 were followed up prospectively. Analysis by mode of delivery showed that of those delivered by caesarean section 23.2% fewer had another pregnancy than those who had a spontaneous vaginal delivery. Women delivered by forceps were in an intermediate group. Miscarriage was more common in women who had been delivered by caesarean section. The relative infertility after caesarean section could not be accounted for by early sterilization, was not associated with maternal height or social status, and was only partly attributable to age.

Adolescent↗
PubMed1987

Therapeutic use of OKT3 monoclonal antibody for acute renal allograft rejection.

OKT3, a murine monoclonal anti-T-cell antibody, was used to treat acute renal allograft rejection crises in 140 patients. When used for primary treatment of initial rejections, it was effective in all 20 recipients of related-donor (RD) grafts and in 70 of 74 recipients of cadaver-donor (CD) grafts. OKT3 was also used for resistant rejection unresponsive to conventional antirejection drugs and was effective in 11 of 13 RD and in 26 of 33 CD recipients. Rerejection occurred in 58% of patients in the OKT3 primary treatment group and in 35% of patients in the OKT3 rescue group. Fifty-nine percent of the patients produced anti-OKT3 antibodies. Nearly all recipients experienced a flu-like syndrome following the first and second daily doses of OKT3. Two-year actuarial patient survivals were 100 and 96% for RD and CD recipients, respectively. In the OKT3 primary treatment group, two-year actuarial RD and CD graft survivals were 91 and 76%, respectively. In the OKT3 rescue group, the two-year actuarial RD and CD graft survivals were 85 and 55%, respectively. A proposed immunosuppressive effect of OKT3 is T-cell inactivation by blocking antigen receptors linked to OKT3-reactive molecules. Reuse of OKT3 for recurrent rejection or subsequent organs may be hampered by anti-OKT3 antibody production. OKT3 is an effective steroid-sparing treatment for renal allograft rejection.

Antibodies, Anti-Idiotypic↗
PubMedDate not supplied

Effects of group CBT on the survival time of patients with metastatic breast cancer.

We have recently reported the psychological outcome of a group Cognitive Behaviour Therapy (CBT) intervention with patients who had metastatic breast cancer. The data of 92 patients who were retained at the first follow-up assessment revealed short-term improvements on measures of mood and self-esteem amongst therapy participants. These changes were not sustained at the 3- and 6-month follow-up assessments. This report describes a survival analysis of 121 patients who entered the study, at 5 years after its commencement. The analysis, based on the Cox Proportional Hazards Regression model, revealed no survival advantage associated with the intervention. Only medical prognostic factors such as Eastern Cooperative Oncology Group (ECOG) performance status, visceral metastases and chemotherapy treatment significantly predicted patients' survival time. The findings of this study are compared with those of two earlier studies which also examined the survival effects of a group psychological intervention with metastatic breast cancer patients.

Adult↗
PubMedDate not supplied

[ECG compression method by using multiple polynomial modelling: comparison with wavelet-changing technique].

The proposed ECG compression combined two approaches, ECG beat alignment and polynomial modeling. QRS complexes are firstly detected then aligned in order to reduce high frequency changes from beat to beat. These changes are modeled by means a polynomial projection. ECG from MIT-BIH database are used to evaluate the performances of the proposed technique. A comparison with the wavelet approach is performed by means the compression ratio (CR) versus the RRD curve.

Algorithms↗
PubMedDate not supplied

Adhesion of silicone to polyurethane in maxillofacial prostheses.

Primers have been reported to increase adhesion between silicone elastomers and polyurethane liners used for maxillofacial prostheses. This study evaluated two primers, three polymerization methods, and seven primer reaction times to determine the conditions for optimum adhesive bond strength. The T-peel strength of specimens was determined as described in ASTM Standard D 1876-72. Failure modes were evaluated, and two-sample t tests and one-way ANOVA were used to compare means for significant (P < .05) differences. Bond strengths were significantly greater for polyurethane treated with primer 1205 rather than S-2260 regardless of the polymerization method or primer reaction time. Neither any single polymerization method nor single primer reaction time consistently yielded greater bond strengths.

Adhesiveness↗