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Biomedical subjects

J Jamieson

Publications and source records attributed to J Jamieson.

At least 19 recordsLinked to original sources
PubMed2006

Use of intravenous immunoglobulin for treatment of recurrent miscarriage: a systematic review.

BACKGROUND: Intravenous immunoglobulin (IVIG) is a fractionated blood product whose off-label use for treating a variety of conditions, including spontaneous recurrent miscarriage, has continued to grow in recent years. Its high costs and short supply necessitate improved guidance on its appropriate applications. OBJECTIVE: We conducted a systematic review of randomised controlled trials evaluating IVIG for treatment of spontaneous recurrent miscarriage. SEARCH STRATEGY: A systematic search strategy was applied to Medline (1966 to June 2005) and the Cochrane Register of Controlled Trials (June 2005). SELECTION CRITERIA: We included all randomised controlled trials comparing all dosages of IVIG to placebo or an active control. DATA COLLECTION AND ANALYSIS: Two investigators independently extracted data using a standardised data collection form. Measures of effect were derived for each trial independently, and studies were pooled based on clinical and methodologic appropriateness. MAIN RESULTS: We identified eight trials involving 442 women that evaluated IVIG therapy used to treat recurrent miscarriage. Overall, IVIG did not significantly increase the odds ratio (OR) of live birth when compared with placebo for treatment of recurrent miscarriage (OR 1.28, 95% CI 0.78-2.10). There was, however, a significant increase in live births following IVIG use in women with secondary recurrent miscarriage (OR 2.71, 95% CI 1.09-6.73), while those with primary miscarriage did not experience the same benefit (OR 0.66, 95% CI 0.35-1.26). AUTHOR'S CONCLUSIONS: IVIG increased the rates of live birth in secondary recurrent miscarriage, but there was insufficient evidence for its use in primary recurrent miscarriage.

Abortion, Habitual↗
PubMed2002

Detection of Chlamydia trachomatis in an Australian high school student population.

OBJECTIVE: To assess the prevalence of Chlamydia trachomatis infections among an Australian high school adolescent population. METHODS: Over a 4 year period, 14 high schools were selected in which an infertility prevention programme targeting C. trachomatis was delivered to senior student populations. Coded first catch urine specimens were analysed by Amplicor PCR and infected students treated. Data retrospectively obtained from chlamydia screening programmes conducted among disadvantaged young people detached from formal education were also collated for comparison. RESULTS: Of a total student test population of 1174, 15 (1.3%; 95% CI 0.7% to 2.1%) were diagnosed with C. trachomatis. Of 516 females and 658 males, 12 (2.3%; 95% CI 1.1% to 4.1%) and 3 (0.5%; 95% CI 0.1% to 1.4%) were tested positive respectively. Data collated for three populations of disadvantaged youth returned at total of 89 C. trachomatis infections out of 560 people (15.9% 95%CI 13.0-19.2%). CONCLUSION: The overall prevalence of C. trachomatis infection among this population of senior high school adolescents is low, and significantly differs from the higher chlamydia rates detected in disadvantaged adolescents detached from formal schooling (p<0.0001).

Adolescent↗
PubMed2001

Application of monitoring data for Giardia and Cryptosporidium to boil water advisories.

Despite the problems associated with analyzing water samples for Giardia cysts and Cryptosporidium oocysts, the data can be very useful if their strengths and weaknesses are understood. Two municipalities in northern Ontario, Temagami and Thunder Bay, both issued boil water advisories for Giardia contamination. Data from these two cities are compared to show that only one municipality experienced a real outbreak, whereas the other did not. The concentration of Giardia cysts was much higher than background during the outbreak at Temagami, and the postoutbreak concentrations of cysts were very similar to the long-term average cyst concentration at Thunder Bay. The waterborne outbreak of giardiasis at Temagami was characterized by consistent positive results from water samples, concentrations two to three orders of magnitude higher than normal, and an obvious increase in the number of cases of giardiasis in the population. No outbreak was experienced at Thunder Bay, but a boil water advisory (BWA) was set in place for more than a year on the basis of a single sample from Loch Lomond in which only two cysts were detected but the sample equivalent volume was low. This gave the impression of a sudden increase in concentration, but 39 of 41 subsequent samples were negative. Additional factors that led to a BWA at Thunder Bay are described, and recommendations are presented to help determine when a BWA is necessary and when it should be rescinded.

Animals↗
PubMed1999

Dealing with baseline differences: two principles and two dilemmas.

Two principles are presented that describe directional confounds associated with baseline differences: Principle 1: Change scores are confounded with baseline whenever data are skewed. Principle 2: When baseline differences are real, ANCOVA has a directional bias that magnifies differences in one direction and masks those in the other direction. Both principles involve a directional bias that is related to the direction of baseline difference and the direction of the hypothesized difference in change. Ethical dilemmas arise if decisions (whether or not to transform, whether or not to use ANCOVA) are chosen in order to maximize power by capitalizing on the directional bias and Type 1 error.

Analysis of Variance↗
PubMed1999

Anesthesia and sedation in the endoscopy suite? (influences and options).

Advances in technology and pharmacology have enabled gastrointestinal endoscopists to expand the diagnostic and therapeutic capabilities of the specialty. Research into the impact of the endoscopy environment on patient stress, acknowledgement of the various patient coping styles, development and deployment of procedural preparative programs and information streamlining have been shown to be of value in decreasing anxiety and reducing sedative requirements. Being aware of procedure-related stressors, and factors associated with complications, allows us to tailor our sedation or anesthesia plan to the individual patient.

Journal Article↗
PubMed1999

Synaptic responses evoked by lower urinary tract stimulation in superior cervical ganglion cells in the rat.

PURPOSE: Stimulation of afferent neurons from the urinary tract can evoke powerful cardiovascular reflexes in animals and in humans. Here we tested whether and to what extent postganglionic sympathetic neurons projecting to the head and neck are involved in these reflexes. MATERIALS AND METHODS: In adult anesthetized female Wistar rats, reflex changes in synaptic activity elicited from the lower urinary tract were recorded in neurons of the superior cervical ganglion using intracellular recording techniques. RESULTS: Gentle movements of the urethral cannula and/or slow injections of 0.3 to 0.6 ml. saline into the bladder modified synaptic activity in 75% of neurons tested: 11/15 neurons tested showed reflexes to urethral stimulation (8 excitatory, 3 inhibitory) and 8/12 neurons responded to bladder distension (5 excitatory, 3 inhibitory). Five neurons showed a reciprocal response pattern to the two stimuli. Suprathreshold and subthreshold inputs to a given cell mostly showed the same type of response. There was no evidence that urinary tract stimulation recruited preganglionic inputs that did not have ongoing activity prior to the stimulus. CONCLUSIONS: Reflexes from the lower urinary tract clearly reached sympathetic neurons located in remote segments. The response incidence in the population studied suggests that most sympathetic neurons involved in cardiovascular regulation participate in these reflexes. The different reflex patterns probably occur in neurons with different functional targets in the head and neck.

Animals↗
PubMed1998

Analysis of the periodicity of synaptic events in neurones in the superior cervical ganglion of anaesthetized rats.

1. The patterns of on-going synaptic events recorded intracellularly in neurones of superior cervical ganglia (SCG)of anaesthetized female rats were analysed by constructing inter-event interval histograms, autocorrelograms, ln-survivor curves and histograms triggered by the arterial pulse wave and by the intercostal EMG. 2. In 11/12 cells with on-going frequencies > 0.5 Hz, one or two inputs were strong (i.e. always suprathreshold). In five cells, action potentials also arose from synaptic potentials with amplitudes close to threshold. 3. Synaptic events in 5/11 neurones tested were phase-related to the arterial pressure wave (i.e. had cardiac rhythmicity, CR). 4. Synaptic events in 9/10 neurones tested (including all with CR) were phase-related to the intercostal EMG and/or their autocorrelograms showed peaks at multiples of the respiratory interval (i.e. had respiratory rhythmicity, RR). 5. The intervals between all synaptic events were exponentially distributed in 8/12 neurones although intervals between single strong events showed peaks related to the respiratory cycle. Bursts occurred only by chance. 6. Event patterns could be simulated by combining events from several respiration-modulated inputs with their timing distributed over nearly half the cycle. From the simulations, the mean number of active preganglionic inputs was estimated to be approximately 6 with mean discharge frequency approximately 0.4 Hz. 7. We conclude that, in the spontaneously breathing anaesthetized rat, most preganglionic neurones to the SCG fire with relatively low probability in relation to the respiratory cycle. Rhythms in a postganglionic neurone reflect the activity of its suprathreshold preganglionic inputs.

Action Potentials↗
PubMed1997

On-going and reflex synaptic events in rat superior cervical ganglion cells.

1. Synaptic events evoked by brief noxious cutaneous stimuli were recorded in sympathetic neurones in the superior cervical ganglion of anaesthetized rats. 2. On-going excitatory synaptic potentials (ESPs) and/or action potentials (APs) were recorded in 69% of neurones at mean frequencies that varied from 0.01 to 6.3 Hz in different cells. From histograms of ESP amplitude during membrane hyperpolarization, it appears that most cells received one (52%), or two or more (36%), suprathreshold inputs and several subthreshold inputs with overlapping amplitudes. 3. Pinching the skin for 1-3 s evoked either a brief burst of synaptic events (lasting about 300 ms) preceding a few seconds of inhibition (burst-inhibitory (BI) neurones), or simply an excitation (excitatory (E) neurones), or no response (O neurones). In 60% of BI neurones, a second burst occurred after the end of the pinch. 4. BI neurones had a higher frequency of on-going synaptic activity (2.9 +/- 0.5 Hz, n = 15) than E neurones (0.2 +/- 0.1 Hz, n = 5) or O (0.2 +/- 0.1 Hz, n = 5) neurones. Most neurones with two or more suprathreshold inputs were BI neurones. In 20% of neurones (all BI with high rates of synaptic activity), several other inputs had ESPs with amplitudes close to threshold. 5. Subthreshold and suprathreshold inputs responded in the same way in only 45% of neurones, but suprathreshold inputs were excited in 73% of BI and all E neurones. The order of recruitment of different inputs varied from trial to trial. If classification was based only on suprathreshold responses, there were 36% BI, 32% E and 32% O neurones. 6. In the majority of neurones, postganglionic discharge was initiated exclusively by suprathreshold inputs, even during reflex excitation. 7. Qualitatively similar, but smaller, responses were evoked by a puff of air on the abdomen in 71% of cells tested. 8. The data suggest that the natural discharge of SCG neurones is largely determined by the activity of one or two preganglionic inputs with high quantal contents. BI neurones may include vasoconstrictor neurones, whereas the other types include secretomotor, pilomotor and other neurones projecting to targets in the head.

Action Potentials↗
PubMed1997

Patterns of classroom discourse in an integrated, interpreted elementary school setting.

The purpose of this study was to describe the patterns of classroom discourse experienced by an integrated deaf child with full-time interpreting services in an elementary setting. The child was videotaped for 3 hours during classroom instructional time. The videotapes were analyzed to determine patterns of discourse between the child and the teacher and the child and the interpreter, as well as to gauge the deaf student's accessibility to teacher-class discourse. It was found that the deaf student interacted predominantly with the interpreter; in fact, this student received more direct instruction from the interpreter than from the teacher. The discourse to which the student was exposed was largely academic, rather than cultural or social. Findings are discussed in terms of the extent to which implicit classroom discourse and cultural knowledge were inaccessible to the deaf student.

Child↗
PubMed1996

Palliation of oesophageal carcinoma using the argon beam coagulator.

Oesophageal intubation occasionally fails to palliate inoperable carcinoma: some tumours are unsuitable for this procedure and others overgrow the tube. This study reports a series of nine patients (median age 79 (range 55-87) years) in whom the argon beam monopolar coagulator via a flexible endoscopic probe was used to ablate such tumours. Fourteen ablation procedures were performed. The endoscope was passed to the stomach at the end of each procedure. There were no complications; the median hospital stay was 2 (range 1-13) days. Thirteen procedures rendered the patients completely asymptomatic for a median of 6 (range 4-12) weeks. Six patients died a median of 14 (range 4-38) weeks after the first ablation, reflecting their limited life expectancy. The argon beam coagulator provides an effective alternative to laser ablation, being considerably cheaper and safer, while maintaining the minimally invasive nature of the palliation.

Aged↗
PubMed1994

Correlates of reactivity: problems with regression based methods.

Computer simulations were used to compare change score and regression methods for identifying relationships between a third variable and reactivity. When the third variable was not correlated with baseline, the two methods were equally effective for detecting relationships between the third variable and change. However when there was a correlation between the third variable and baseline, regression measures of change yielded a high rate of Type one errors. Regression methods also had less power for detecting a relationship between the third variable and change when the relationship was in the direction opposite to the sign of the correlation with baseline. The implication of these findings for two areas of research are discussed: the relationship of fitness to heart rate reactivity and the relationship of hypertension to blood pressure reactivity.

Computer Simulation↗
PubMed1993

The law of initial values: five factors or two?

We (Jamieson and Howk (1992) Int. J. Psychophysiol. 12, 53-61) recently used computer simulations to study factors affecting the correlation between change and initial level (rdx). Four factors were identified: (1), measurement error; (2), floor/ceiling effects (the 'real Law of initial values'); (3), reactivity and (4), skewness. The present study used the same approach to show that a fifth factor, change in variance from pre to post, was also capable of influencing rdx. When the variance increased, rdx became positive; when the variance decreased, rdx became negative. These five factors appear to affect rdx through only two underlying mechanisms: regression to the mean and variance change. The difficulty of separating a 'real Law of initial values' from the other factors is discussed.

Analysis of Variance↗
PubMed1992

Effect of Nissen fundoplication on esophageal motor function.

The effect of Nissen fundoplication on the compromised esophageal body function in patients with gastroesophageal reflux disease is poorly understood. Stationary manometry of the distal esophageal body was performed in 50 normal volunteers and compared with that in 40 patients with increased esophageal acid exposure. The studies were performed before and 11 to 68 months (median, 30 months) after successful reflux control and healing of acute mucosal injury with Nissen fundoplication. Before the operation, patients had a lower mean amplitude of contractions, higher prevalence of low amplitude, and interrupted and simultaneous contractions in the distal esophagus compared with normal volunteers. Nissen fundoplication restored the lower esophageal sphincter to normal, increased contraction amplitude, and reduced the prevalence of low-amplitude contractions but did not improve contraction amplitude in patients with a mean amplitude below 35 mm Hg. Fundoplication improves esophageal contraction amplitude but should be performed before the mean contraction amplitude falls below 35 mm Hg.

Circadian Rhythm↗
PubMed1992

The law of initial values: a four factor theory.

The effects of four factors, measurement error, skewness, floor/ceiling effects, and reactivity, on the correlation between change and initial level were studied using computer simulations. A total of 24 conditions were simulated: the four factors being examined together with variations in the direction of change, level of measurement error and/or strength of effect. In each condition ten random samples of 50 cases were generated by SPSSX, and compute functions were used to model the effects of interest. Three factors were capable of producing a negative correlation (the Law of Initial Values, LIV): measurement error, skewness, and floor/ceiling effects. Two factors yielded a positive correlation (anti-LIV effect): reactivity and skewness. The issue of how to determine which factor is operating in a given situation is discussed.

Biology↗
PubMed1991

Three-dimensional imaging of the lower esophageal sphincter in gastroesophageal reflux disease.

The resistance of the lower esophageal sphincter to reflux of gastric juice is determined by the integrated effects of radial pressures exerted over the entire length of the sphincter. This can be quantitated by three-dimensional computerized imaging of sphincter pressures obtained by a pullback of radially oriented pressure transducers and by calculating the volume of this image, in other words, the sphincter pressure vector volume. Validation studies showed that sphincter imaging based on a stepwise pullback of a catheter with four or eight radial side holes is superior to a rapid motorized pullback. Compared with 50 healthy volunteers, the total and abdominal sphincter pressure vector volume was lower in 150 patients with increased esophageal acid exposure (p less than 0.001) and decreased with increasing esophageal mucosal damage (p less than 0.01). Calculation of the sphincter pressure vector volume was superior to standard techniques in identifying a mechanically defective sphincter as the cause of increased esophageal acid exposure, particularly in patients without mucosal damage. The Nissen and Belsey fundoplication increased the total and intra-abdominal sphincter pressure vector volume (p less than 0.001) and normalized the three-dimensional sphincter image. Failure to do so was associated with recurrent or persistent reflux. These data indicate that three-dimensional imaging of the lower esophageal sphincter improves the identification of patients who would benefit from an antireflux procedure. Analysis of the three-dimensional sphincter pressure profile should become the standard for evaluation of the lower esophageal sphincter.

Adult↗
PubMed1990

Perceptions of athletic injuries by athletes, coaches, and medical professionals.

35 athletes, their coaches, and medical professionals independently assessed the disruption, seriousness, and short-term effects of the athletes' athletic injuries. Athletes underestimated the disruption and short-term effects of the injury when compared to medical professionals. 25 lower level athletes and those with no previous serious athletic injury overestimated the short-term effects of their injuries. Coaches overestimated the disrupting effects of the injury for 10 higher level athletes and 25 athletes with no previous injury.

Activities of Daily Living↗
PubMed1989

Analysis of thirty-two patients with Schatzki's ring.

Schatzki's ring is a distinct anatomical entity associated with hiatal hernia; however, its significance is unclear. Thirty-two patients with a radiologically demonstrated Schatzki's ring were compared with 32 patients with hiatal hernia and no Schatzki's ring. Schatzki's ring was confirmed on endoscopy in 59 percent of patients. Seventy-five percent of patients with Schatzki's ring presented with dysphagia compared with 41 percent of control patients (p less than 0.01). Heartburn and regurgitation were less frequent than in control subjects (38 percent versus 91 percent, p less than 0.0001). Schatzki's ring patients were found to have a lower incidence of proven gastroesophageal reflux on 24-hour pH monitoring. Those with proven reflux were found to have a more efficient lower esophageal sphincter than control patients. Sixty-two percent of Schatzki's ring patients without proven reflux had a history of chronic ingestion of drugs known to be damaging to the esophageal mucosa, whereas only 26 percent of patients with reflux had this history. This was found in 16 percent of controls. Sixty-two percent of Schatzki's ring patients without reflux responded to a single dilatation compared with 37 percent of those with reflux. These findings suggest an etiologic relationship between pill lodgement and Schatzki's ring in patients without reflux and indicate that different therapy should be employed in these patients.

Adult↗