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Biomedical subjects

R A Cole

Publications and source records attributed to R A Cole.

14 recordsLinked to original sources

Further development and automation of a high pressure liquid chromatography method for the determination of glycosylated hemoglobins.

A previously described high pressure liquid chromatography system for the determination of glycosylated hemoglobin concentrations has been automated and simplified. With this methodology it is possible to perform up to 60 analyses per day for hemoglobin A1a+b% and hemoglobin A1c%. Where an estimate of the total fast hemoglobin alone is required, then a considerably greater number of analyses can be performed. The individual values are calculated directly with an electronic integrator. The mean coefficient of variation of the duplicate determinations of 48 samples was 0.63 +/- 0.83% (mean +/- SD). Aliquots of pooled hemolysates have been maintained in liquid nitrogen at -90 degrees C and run at the beginning and end of each daily analytical run over an 18-mo period. Both the inter- and intra-run coefficients of variation of these values have remained consistently less than 3%. Therefore, the methodology offers a reliable and accurate method of containing glycosylated hemoglobin values for clinical use.

Autoanalysis

Hemophilus parainfluenzae endocarditis.

We describe a case of Hemophilus parainfluenzae endocarditis in a previously healthy 26-year-old man, and review 21 cases from the literature. Although H parainfluenzae is considered to be part of the normal flora of the upper respiratory tract in man, it can cause serious disease. H parainfluenzae endocarditis is often difficult to diagnose. The patients generally had a history of recent infection of the upper respiratory tract, but a majority denied previous heart disease. Upon entry to the hospital, after an average of seven weeks of febrile illness, nearly one third of patients were found not to have a heart murmur. Furthermore, the organism was often difficult to grow from blood cultures, a problem possibly related to the need for accessory growth factors. The mortality with modern therapy was 12%, and the major complication was cerebral embolus. Antibiotic therapy of choice is ampicillin, generally used together with an aminoglycoside, though ampicillin alone may be sufficient.

Adult

The effect of laparoscopic sterilisation by diathermy or silastic bands on post-operative pain, menstrual symptoms and sexuality.

A total of 530 patients was reviewed six months after laparoscopic sterilisation by diathermy (235 patients) or silastic bands (295 patients). In the immediate postoperative period severe lower abdominal pain was more common in the patients who had silastic bands. There was no differences in the nature or incidence of menstrual problems when the two methods were compared. In all, 40 per cent of patients reported an increase in menstrual blood loss ad 26 per cent of patients an increase in menstrual pain, and this could not be attributed entirely to stopping oral contraception; 42 per cent of patients reported improvement in their sex lives after sterilisation, while 6.6 per cent reported deterioration mainly due to lack of libido. There was some regret about the operation in 5.1 per cent of patients.

Diathermy

Reproducibility of hemoglobin AIc and sensitivity to various degrees of glucose intolerance.

To establish a normal range of hemoglobin (Hb) AIc, and ascertain the sensitivity and reproducibility of this test, three groups were studied: patients with suspected diabetes undergoing a standard oral glucose tolerance test, diabetic outpatients, and subjects with normal carbohydrate tolerance studies on two separate occasions. In Group 1, the mean Hb AIc (+/- SD) in 165 carbohydrate-tolerant subjects was 4.97 +/- 0.50% and the normal range was the mean +/- 2 standard deviations (4.0 to 6.0%). The mean Hb AIc (+/- SD) of the 63 carbohydrate-intolerant subjects was 6.45 +/- 1.14, significantly greater than the normal subjects. In both subgroups, Hb AIc correlated significantly with the fasting blood glucose but not with the glucose areas of the oral glucose-tolerance test. In Group 2, the Hb AIc values were normal in 39% of those diet treated, 10% of those on oral agents, and none of those on insulin therapy. In Group 3, the mean coefficient of variation of the two Hb AIc values for each subject was 6.86% but was 7.15% for the fasting blood glucose. These findings suggest that Hb AIc is highly reproducible and responsive to minor degrees of abnormality of glucose tolerance and may provide an alternative method for defining carbohydrate tolerance or the degree of blood sugar control.

Adolescent

A rapid method for the determination of glycosylated hemoglobins using high pressure liquid chromatography.

Hemoglobin (Hb) Alc is a minor component of Hb found in normal individuals but elevated two or threefold in patients with diabetes mellitus. Limited studies have suggested that the level of Hb Alc is proportional to the integrated concentration of glucose over time. Thus it could serve as an index of hyperglycemia. Its measurement may enable a more objective approach to assessing whether or not the control of hyperglycemia can be correlated with the severity of complications of diabetes. Large scale clinicab studies of Hb Alc have not been undertaken for lack of a rapid assay system. This article describes a method of high pressure liquid chromatography (HPLC) which enables the isolation of Hb Alc in 27 min using only 12 microgram of Hb (100 microliter of blood) and a second method for the isolation of total fast Hb components (also elevated in diabetes) in 11 min. Using the first method, a total of 36 assays were performed on the blood of a single normal volunteer over a one month period. the mean level of Hb Alc was 4.95 +/- 0.12% (SD) +/- 0.02% (SEM), while the coefficient of variation (C.V.) was 2.4%. The mean Hb Alc & b level was 1.65 +/- 0.06% +/- 0.01% (C.V. = 3.6%). Values for Hb Alc in 10 normal individuals were 5.06 (mean) +/- 0.32% (SD) +/- 0.01% (SEM). Hb Alc values in 15 patients with diabetes mellitus ranged from 6.8 to 20.0%. The second method was designed to assay Hb Ala, Hb Alb, and Hb Alc as a single peak and yielded results identical to the sum of these components as determined by the first method ( r = 0.98; p less than 0.001).

Chromatography, High Pressure Liquid

Perceptibility of phonetic features in fluent speech.

A series of experiments examined listeners' ability to detect mispronounced words in a short story. Mispronunciations were produced by changing a single consonant segment in a word to produce a (phonologically permissible) nonsense word. The results of six different experiments showed that prestressed work-initial stop consonants are more perceptible than other consonants. For example, mispronunciations produced by changing the voicing of a word-initial stop (e.g., "boy" to "poy") were detected about 70% of the time, while changes in voicing of a word-initial fricative (e.g., "voice" to "foice") were detected about 38% of the time. Mispronunciations produced by changing the place of articulation of a prestressed word-initial stop were most detectable of all (80% to 90% detection) for three different speakers. A change in place of articulation of a word-initial stop (e.g., "baby" to "daby") was detected as often as a change in both place of articulation and voicing (e.g., "baby" to "taby"). Finally, it was found that a mispronunciation was detected about twice as often in word-initial than in word-final position in one syllable words for both stops and nasals. The results suggest that listeners pay special attention to word-initial stop consonants in natural continuous speech.

Humans

Blood glucose monitoring in symptomatic hypoglycemia.

The relationship between blood glucose levels and the onset of hypoglycemic symptoms was studied by continuous monitoring of blood glucose levels after an oral glucose load in nine adults with normal glucose tolerance, five with chemical diabetes without symptomatic hypoglycemia, and nine with chemical diabetes with symptomatic hypoglycemia. Symptoms were associated not only with a low level of blood glucose but with a rapid fall as well. These two parameters were used to calculate a "hypoglycemic index" (defined as the fall in blood glucose during a 90-minute period prior to reaching the minimum level, divided by the value of this minimum level). The hypoglycemic index was 2.3 +/- 0.6 (mean +/- S.D.) in the group of diabetic patients with symptomatic reactive hypoglycemia and 0.7 +/- 0.3 for the other groups. This index may aid in the diagnosis of patients with symptoms of hypoglycemia and equivocally low values of blood glucose.

Adult

Elective induction of labour. A randomised prospective trial.

In a prospective, randomised trial, 111 obstetrically normal pregnant women, who had elective induction of labour performed between 39 and 40 weeks, were compared with 117 controls who were managed expectantly until 41 weeks. Compared with the controls, the patients who had elective induction of labour had significantly less meconium staining in labour and a smaller blood-loss after delivery. The mean length of labour, the amount of pethidine used, and the Apgar scores at 1 minute were similar in the two groups. In the electively induced group, the caesarean-section rate was lower and the use of epidural analgesia more common than in the controls, but the differences were mot statistically signficant. The hour of delivery was similar in the two groups, suggesting that convenience to medical and nursing staff would not be greatly changed by elective induction of labour. There was no evidence that the hazards to mother and child were increased by elective induction, and its use might improve perinatal mortality by reducing the number of unexplained mature stillbirths.

Adolescent

Effect of subvocalization on memory for speech sounds.

Subjects in two groups were presented with sequences of 6 consonant-vowel syllables for ordered recall. Subjects in both groups were trained to suppress subvocalization. Only subjects in the feedback group were asked to suppress subvocalization during the experiment, while subjects in the no-feedback group were allowed to subvocalize during the memory task. Analysis of the electromyographic records showed a large decrease in subvocalization in the feedback condition, and results of the memory task revealed an increase in errors for this group. However, a comparison of errors within each group revealed an identical pattern of overall errors and intrusion errors on subvocalization and nonsubvocalization trials, and these results were identical in both groups. The results suggest that requiring subjects to simultaneously suppress subvocalization and remember syllables depresses performance slightly, but encoding of speech sounds in short-term memory occurs independently of subvocal activity during the memory task.

Auditory Perception