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Biomedical subjects

N McIntosh

Publications and source records attributed to N McIntosh.

At least 37 records · Page 2Linked to original sources
PubMed1994

Changes in mean blood pressure caused by damping of the arterial pressure waveform.

'Damping' of an intra-arterial pressure waveform theoretically affects systolic and diastolic blood pressure whilst mean blood pressure (mbp) continues to be reliable. We assessed changes in mbp associated with 79 episodes of damping in 30 infants. The average mbp in the hour just before damping occurred was compared with that in the first hour of damping. The mean change in mbp was -0.845 mmHg. In 50% of cases this change was < 2 mmHg and in 24% of episodes > or = 4.1 mmHg. Damping may produce clinically significant changes in mbp which computer trend data may help to differentiate.

Blood Pressure↗
PubMed1994

Hydrops foetalis and chylothorax associated with superior caval vein obstruction and resolution following balloon dilatation.

A female infant (33 weeks' gestation) was delivered by emergency caesarean section because of hydrops foetalis. No cause was identified initially; haemoglobin, liver and renal functions were normal and there was no evidence of sepsis or significant myocardial dysfunction or arrhythmia. There was initial improvement with conventional management but bilateral pleural effusions persisted, which became overtly chylous after institution of enteral formula feeds on day 4. At 5 weeks of age, an obstruction at the superior caval vein/right atrial junction was confirmed at angiography and dilated with resolution of all remaining oedema and fluid collections. Repeat venography at 9 months of age showed a normal superior caval vein and she remains well at 15 months.

Catheterization↗
PubMed1994

Alleviation of the pain of heel prick in preterm infants.

The hypothesis that the variability of physiological parameters may indicate pain or stress in the neonate was examined. Four parameters (heart rate, respiratory rate, transcutaneous oxygen tension, and carbon dioxide tension) were examined over a 2 minute epoch in response to a heel prick in an attempt to measure stress/pain in 35 preterm newborn infants (26-34 weeks' gestation) half of whom were receiving intensive care. The change in absolute values of these parameters did not discriminate a dummy procedure without prick from the actual procedure containing the prick (paired t test), but the variability of the parameters during an epoch showed significant discrimination. Three procedures were evaluated to reduce this distress using unpaired t test. The use of local anaesthetic cream was not successful. The components of the mixture cause vasoconstriction that would reduce blood flow to the heel and lead to more squeezing which is likely to be painful in the presence of tissue damage. A nurse comforting the infant with tactile and vocal stimulation was slightly helpful but the use of a spring loaded lance was most successful in reducing the distress. The use of spring loaded lances may be more humane for heel pricks.

Anesthetics, Local↗
PubMed1994

A portable dual energy x-ray absorptiometry technique for the measurement of bone mineral in preterm infants.

A dual energy x-ray absorptiometry technique has been developed for the measurement of bone mineral in preterm infants. Two films are taken of the infant's forearm using a standard mobile x-ray set on the ward at two x-ray energies. Included in the field of view is a double step wedge made of aluminum and Perspex. The images are digitized by viewing them on a light box with a TV camera. The bone mineral content in the forearm can then be mapped by the measurement of light intensity in matching pixels of the two films and comparison with the intensities in the step wedge. The bone mineral concentration in the radius, expressed as bone mineral per unit length (mg/mm), is calculated. The technique has been tested using phantoms of calcium hydroxylapatite set in a tissue equivalent material and in Perspex. It has been shown that the reproducibility of the technique is approximately 7% and that there is a systematic underestimate of bone mineral of about 17%. The technique has been shown to be linear up to a bone mineral concentration of 8 mg.mm-1. Longitudinal studies for 14 infants that show an initial 6-wk period of demineralization after birth with a subsequent mineralization phase are reported.

Absorptiometry, Photon↗
PubMed1993

Pitfalls in the use of ELISA to screen for monoclonal antibodies raised against small peptides.

Small peptides are often conjugated to large carrier proteins such as thyroglobulin to increase their immunogenicity. Antibodies are raised against peptide, thyroglobulin and contaminants, such as immunoglobulins or BSA in the thyroglobulin preparation, but anti-contaminant antibodies will not be revealed if immune serum is diluted in buffer containing immunoglobulin-contaminated BSA. This may lead to the development of an inappropriate hybridoma-screening assay which detects more anti-contaminant than anti-peptide antibodies if ELISA plates are coated with a capture antibody or blocked with BSA. Dilution of culture supernatants in buffer containing BSA and Tween 20 minimises the risk of false positive results and makes plate-blocking unnecessary. The high affinity peptide-specific antibodies in immune serum, which are more readily detected than lower affinity monoclonal antibodies, may result in an inadequately sensitive hybridoma-screening ELISA.

Animals↗
PubMed1993

Transcervical CVS sample size: correlation with placental location, cytogenetic findings, and pregnancy outcome.

Data from 2907 transcervical CVS cases performed on singleton pregnancies were reviewed retrospectively and villus sample size was correlated with cytogenetic results, placental location, maternal age at the expected date of confinement (EDC), gestational age at the time of sampling, birth weight, gestational age at the time of delivery, and pregnancy outcome. No correlation was noted between villus sample size and maternal age, gestational age at sampling, gestational age at delivery, birth weight, or pregnancy outcome. An inverse correlation between villus sample size and percentage of abnormal cytogenetic findings was statistically significant (chi 2 = 8.53, p < 0.01). The percentage of small samples was greater when the placenta was anterior, lateral, or fundal than when the placenta was posterior.

Adult↗
PubMed1993

Cyclical variation of blood pressure and heart rate in neonates.

Using a computerised physiological monitoring system a cyclical variation in blood pressure (waves), with associated changes in heart rate and transcutaneous oxygen, was observed. Twenty five episodes were seen in 10 neonates, with a median gestation of 33 weeks (range 28-42 weeks). Eight neonates had an asphyxial injury. Blood pressure waves had a mean (SD) amplitude of 11.6 (5.6) mm Hg with a mean wavelength of 9.0 (5.2) minutes. Both amplitude and frequency were independent of gestation. In neonates of less than 34 weeks an inverse phase relation existed between heart rate and blood pressure waves (blood pressure rose as heart rate fell); in infants with a gestation greater than 34 weeks a direct phase relationship occurred (blood pressure and heart rate rose together). It is postulated that hypertensive blood pressure waves may cause or exacerbate cerebral pathology in neonates with a pressure passive cerebral circulation.

Blood Gas Monitoring, Transcutaneous↗
PubMed1992

Pulmonary atresia with intact ventricular septum and hypoplastic right heart in sibs: a single gene disorder?

We report on 2 sisters with hypoplastic right heart and pulmonary atresia. The first sib was found to have pulmonary atresia, intact ventricular septum, and hypoplastic right heart after delivery. Fetal echocardiography at 22 weeks of gestation during the second pregnancy documented the same cardiac abnormalities. Autopsy findings in the fetus confirmed the echocardiographic findings. No other malformations were detected in either case, and no other affected relatives were identified. We suggest that this rare congenital heart defect may, in some cases, be an autosomal recessive trait.

Adult↗
PubMed1992

Ebstein anomaly: report of a familial occurrence and prenatal diagnosis.

The Ebstein anomaly is a rare congenital heart disease involving the position and structure of the tricuspid valve. Although most cases are sporadic, familial occurrence has been documented. We report on 2 sisters, born to consanguineous parents, who were diagnosed prenatally with severe Ebstein anomaly.

Adult↗
PubMed1992

Neonatal physiological trend monitoring by computer.

A premature baby born up to four months early is a fragile patient dependent on intensive care. The body systems are physiologically immature and so tolerate stress badly. The tendency of these infants to rapidly deteriorate, has led us to use a cotside computer monitoring system which displays physiological trends. Information from standard neonatal monitors is accessed by individual cotside PC's linked to a central network server and Doctors terminal. Trend graphs can be easily manipulated, displaying from 7 minutes to 3 days of physiological information on a single screen. Pathology may be observed in real time as it occurs. The system has 3 main areas of use, (a) as a real time clinical aid to patient management, e.g. apnoea of the newborn; (b) as a research tool, demonstrating the effects of procedures on physiology; (c) for educating members of staff about how physiological events develop. Data is saved for the whole of each neonates intensive care stay. Assessment of staff and parent attitudes by questionnaire have been favourable.

Humans↗
PubMed1991

Costello syndrome.

In 1971, Costello described a new syndrome in 2 patients. The major clinical findings comprise short stature; redundant skin of the neck, palms, soles, and fingers; curly hair; relative macrocephaly; depressed nasal bridge; papillomata around the mouth and nares; distinct facial gestalt; hyperextensible joints; and mental retardation. We present a third patient and review the manifestations of this condition.

Abnormalities, Multiple↗
PubMed1991

The effect of the Angelchik prosthesis on esophageal and gastric function.

The effects of the Angelchik prosthesis on esophageal and gastric function were investigated in 17 patients (11 men and six women; median age, 57 years; age range, 36 to 88 years) who underwent surgery for treatment of gastroesophageal reflux disease. All patients demonstrated unequivocal reflux, either at endoscopy or 24-hour pH testing. There was a significant increase in lower esophageal sphincter pressure after surgery, and no patient demonstrated abnormal reflux on pH testing. Gastric emptying of liquids and solids was not altered by surgery. Six months after surgery, all symptoms except dysphagia had significantly improved. Thirty-three months after surgery, six patients described symptoms as severe as or worse than those before surgery. Four patients had the prosthesis removed, two because of dysphagia alone, one because of reflux and dysphagia, and one because of flatulence and bloating. The patients who required removal of the prosthesis because of dysphagia had gross delay of esophageal emptying. We conclude that the Angelchik prosthesis is an effective antireflux device, but it interferes with esophageal function in some patients, requiring removal of the prosthesis. We think the rate of removal of the prosthesis is too high for its routine use in the treatment of gastroesophageal reflux disease.

Adult↗