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Biomedical subjects

M Norman

Publications and source records attributed to M Norman.

At least 55 records · Page 3Linked to original sources
PubMed1998

Improved lung function and quality of life following increased elastic recoil after lung volume reduction surgery in emphysema.

Lung volume reduction surgery for severe emphysema with removal of 20-30% of the most destroyed parts of the lung parenchyma has been reported to improve lung function substantially. Increased elastic recoil has been suggested as one underlying mechanism for the improvement. Fourteen patients, seven men and seven women with a mean age of 62 years, who underwent bilateral lung volume reduction surgery have been followed up for 3 months. We here report the data on quality of life, lung function and elastic recoil. FEV1.0 increased by a mean of 26% from 0.581 to 0.731 (P < 0.01). The mean TLC was reduced by 16% from 8.91 to 7.51 (P < 0.001). The level of hyperinflation decreased as implied by a reduction in the ratio of RV to TLC from 0.70 to 0.60 (P < 0.001). The pulmonary elastic recoil improved, with an increase in the transpulmonary pressure at maximal inspiration (PelTLC) from 0.95 kPa to 1.35 kPa (P < 0.05) and an average increase in the coefficient of retraction PelTLC/TLC) from 0.12 kPa l-1 to 0.19 kPa l-1 (P < 0.01). The resting PaO2 increased from a mean of 8.7 kPa to 9.8 kPa (P < 0.01). The patients reported a high degree of subjective improvement according to the St. George's Respiratory Questionnaire and the working capacity on a bicycle increased by 26% from a mean of 38 W to 48 W (P < 0.01). The promising short-term results of lung volume reduction surgery for severe emphysema appear to be related to improved pulmonary elastic recoil.

Aged↗
PubMed1998

Medical examiner cases associated with previously undiagnosed diabetes mellitus, North Carolina, 1994.

BACKGROUND: Approximately half of the 16 million Americans with diabetes mellitus (DM) are unaware they have the disease; the epidemiology of death from previously undiagnosed DM is unclear. We report medical examiner (ME) cases of death from DM in North Carolina in 1994 to determine the number and characteristics of these cases. METHODS: Deaths from DM ICD-9 were identified and reviewed. RESULTS: Of the 42 cases ascertained from ME records, 6 had previously undiagnosed DM, 5 had diabetes ketoacidosis, and 1 had nonketotic hyperosmolar hyperglycemia. Mean patient age at death for all cases was 42 years (range, 35 years to 57 years). Four patients felt bad at least 24 hours before death, indicating that they are not technically "sudden deaths." CONCLUSIONS: We provide a limited epidemiologic perspective of the phenomenon of death from undiagnosed DM. We suggest further investigation of mortality from previously undiagnosed diabetes.

Adolescent↗
PubMed1998

Increased large arterial stiffness and impaired acetylcholine induced skin vasodilatation in women with previous gestational diabetes mellitus.

OBJECTIVE: Gestational diabetes is associated with increased risk of developing noninsulin-dependent diabetes (NIDDM) later in life. By the time that a diagnosis of NIDDM is established, functional disturbances in the vascular system may be observed. This study was planned to assess macro- and microvascular function in nonpregnant women without signs of diabetes two to four years after a pregnancy complicated with gestational diabetes. DESIGN: Cross-sectional study. SETTING: Vascular research laboratory in the obstetric unit of a university hospital. PARTICIPANTS: Seventeen nonpregnant, healthy women with a history of gestational diabetes and 20 nonpregnant control women of similar age without previous diabetes. METHODS: For quantification of the mechanical properties in large arterial vessels the wall movements of the abdominal aorta and left common carotid artery were recorded with an ultrasonic tracking system. Microvascular perfusion in the skin of the hand and foot was recorded by a laser Doppler technique to assess the vasodilatory response induced by transcutaneous acetylcholine. RESULTS: Women in the gestational diabetes group showed evidence of increased wall stiffness in the common carotid artery and a lower maximum incremental velocity of the pulsatile vessel diameter change in both aorta and carotid artery compared with controls. Acetylcholine induced vasodilatation in both hand and foot was lower in women with previous gestational diabetes compared with controls. CONCLUSION: Abnormal vascular function was found in asymptomatic women with a history of gestational diabetes. It is speculated that these abnormalities might be early evidence of vascular complications associated with subsequent NIDDM.

Acetylcholine↗
PubMed1998

A study of the acoustic reflex using fast-rate otoacoustic emissions.

Fast-rate otoacoustic emissions (OAEs) were used to determine the inward and outward transmission change produced by the stapedial muscle reflex. The subjects were otologically normal adult volunteers. Satisfactory recordings were obtained from a total of 16 ears. Runs of 16 click-evoked OAEs were recorded at a rate of 4282 clicks/s using the maximum length sequence (MLS) technique, with a contralateral tone presented at 10 dB above the contralateral acoustic reflex threshold during the recording of OAEs 5-12 in each run. The OAEs recorded with the contralateral tone were compared with those recorded without the tone to determine the effect of the acoustic reflex. An analysis of the OAEs in 0.5 kHz frequency bands suggested that the reflex produced significant attenuation of low frequency sound with smaller effects at high frequencies, which included amplification for some subjects. For eight of the 16 ears there was an increase in OAE amplitude with the acoustic reflex for at least one frequency band. At low frequencies (1, 1.5 kHz) the inward transmission change produced by the acoustic reflex appeared to be similar in magnitude to the outward transmission change.

Acoustic Stimulation↗
PubMed1997

Prolactin stimulates the JAK2 and focal adhesion kinase pathways in human breast carcinoma T47-D cells.

Treatment of T47-D human breast carcinoma cells with recombinant prolactin (rhPRL) induced a concentration- and time-dependent increase in the phosphotyrosine content of JAK2. rhPRL also stimulated JAK2 tyrosine phosphorylation more weakly in three other breast carcinoma lines, MCF-7, ZR-75-1 and MDA-MB-231. Furthermore it stimulated tyrosine phosphorylation of two isoforms of the transcriptional activator STAT5, STAT5a and STAT5b. Surprisingly, rhPRL treatment of T47-D cells also stimulated tyrosine phosphorylation of focal adhesion kinase (FAK), as determined by immunoprecipitation with anti-phosphotyrosine antibody followed by immunoblotting with a specific FAK antibody. The effect of rhPRL was rapid and concentration-dependent, being maximal at 5 ng/ml. At rhPRL concentrations above 25 ng/ml, FAK tyrosine phosphorylation declined but remained above control levels at 100 ng/ml. rhPRL also stimulated paxillin tyrosine phosphorylation in T47-D cells with similar concentration- and time-dependence. In a second human breast carcinoma cell line, MCF-7, rhPRL produced very similar effects on FAK and paxillin tyrosine phosphorylation. These findings identify a new protein tyrosine kinase pathway in the action of the lactogenic hormone rhPRL and represent the first report that a hormone acting through a member of the haemopoietin receptor superfamily can regulate the FAK/paxillin pathway.

Breast Neoplasms↗
PubMed1997

Intrathecal sufentanil, fentanyl, or placebo added to bupivacaine for cesarean section.

UNLABELLED: We compared the effects of intrathecal sufentanil 2.5 and 5 microg, fentanyl 10 microg, and placebo when administered together with hyperbaric bupivacaine 0.5% 12.5 mg for cesarean section. The study was performed in a randomized, double-blind fashion in 80 (20 per group) healthy, full-term parturients presenting for elective cesarean section. Postoperative pain was assessed using the visual analog scale (VAS). Duration of complete analgesia was defined as the time from the intrathecal injection to VAS score > 0. Duration of effective analgesia was defined as the time to VAS score > or = 4. No patient experienced intraoperative pain. Complete analgesia was prolonged in all groups receiving opioids. Effective analgesia was prolonged and the 0- to 6-h intravenous opioid requirements were lower in the groups receiving sufentanil compared with those receiving fentanyl and placebo. The need for intraoperative antiemetic medication was greater in the placebo group. Pruritus was a frequent and dose-related side effect in the groups receiving sufentanil. There were no differences in umbilical cord blood gases or neonatal Apgar scores and neurological and adaptive capacity scores among the groups. In conclusion, the addition of sufentanil or fentanyl improved the quality of subarachnoid block compared with placebo. The duration of action was longer for sufentanil than fentanyl. IMPLICATIONS: Small doses of fentanyl or sufentanil (synthetic opioids) added to bupivacaine (local anesthetic) for spinal anesthesia for cesarean section reduce the need for intraoperative antiemetic medication and increase the duration of analgesia in the early postoperative period compared with placebo.

Adult↗
PubMed1997

Intermittent auscultation for the intrapartum assessment of fetal well-being in Western Australia.

In May 1995, in response to a decision of the Perinatal and Infant Mortality Committee of Western Australia, a survey of Western Australian hospitals was performed to ascertain what policies were in use for the monitoring of the fetal heart rate in labour and what proportion of these hospitals had access to electronic monitoring by cardiotocography. A response was received from 96% of the surveyed hospitals. More than half the births in this State (13,950 of 25,238) were monitored in labour using intermittent auscultation as the primary test; 7.5% of Western Australian births each year occurred in hospitals in which electronic monitoring was not available. Fewer than 50% of hospitals had written protocols describing the method of auscultation of the fetal heart during labour, the indications to contact a doctor or the management of fetal distress. The protocols which did exist displayed considerable variation in the recommended frequency of intermittent auscultation. The lack of standard practice in this field probably results from uncertainties in the literature. Intermittent auscultation has not been subjected to rigorous scientific evaluation as a screening tool and guidelines documenting ideal auscultatory practices need to balance the precision of electronic monitoring and freedom from intervention. Based on this compromise and existing evidence, a protocol for intermittent auscultation in normal labour is proposed.

Cardiotocography↗
PubMed1997

Skin microcirculation before and after local warming in infants delivered vaginally or by caesarean section.

To elucidate early postnatal changes in skin microcirculation, term newborn infants were studied at 2, 6 and 24 h after vaginal delivery (VD, n = 20) or elective caesarean section (CS, n = 10). Laser Doppler technique was used to measure perfusion, rhythmical perfusion changes, i.e. vasomotion, and reactive hyperaemia of the dorsal hand, before and after local warming of the skin to 37 degrees C. The skin perfusion and the magnitude of reactive hyperaemia (mean 85%) remained essentially unchanged, while vasomotion increased from 0-5 to 2-8 cycles/min (p < 0.001) during the first day of life. Local warming of the skin promoted microcirculation slightly at 2 h and more markedly at 24 h postnatal age. The CS group showed a higher degree of skin perfusion, vasomotion and reactive hyperaemia than did VD infants at 2 h postnatal age. Our findings most likely reflect skin microcirculatory effects of birth-related events, such as a drop in body temperature, sympathoadrenal activation and placental transfusion.

Blood Pressure↗
PubMed1997

Dynamic properties of the aorta and of the foot microcirculation in adolescents with diabetes mellitus.

To evaluate vascular function in diabetic subjects, we studied both the stiffness of the abdominal aorta and the foot microvascular reactivity in 22 diabetic adolescents and 18 controls. The aortic stiffness was significantly higher in diabetic females, but not in males, as compared to age- and gender-matched controls (p < 0.05). Foot post-ischaemic hyperaemia was lower in diabetic subjects than in controls (p < 0.05), while postural vasoconstriction did not differ between the groups. The microvascular reactivity did not correlate with the duration of diabetes, but seemed to be influenced by the insulin regimen. The degree of aortic stiffness and the microvascular reactivity of the foot were not significantly interrelated. Loss of aortic elasticity might be a long-term effect of diabetes, whereas microvascular reactivity seems to reflect the current influence of the metabolic state and insulin treatment.

Adolescent↗
PubMed1997

Endogenous nitric oxide in the upper airways of premature and term infants.

Concentrations of endogenous nitric oxide (NO) were measured in premature (n = 18) and term infants (n = 7). Nasal gas was aspirated continuously and after timed occlusions, 15 s and 60 s, by a fast-response chemiluminescence analyser. The sampling flow rate was 20 ml min-1. Typical NO recordings consisted of plateaux and postocclusive peaks. In term infants peak NO concentrations (60 s occlusion) were 2.71 +/- 0.44 parts per million (ppm) within 10 min after birth, increasing (p < 0.05) to 3.81 +/- 0.25 ppm at 4-7 d postnatally. Peak NO values (15 s occlusion) averaged 1.22 +/- 0.16 ppm in premature infants (postconceptional age 25-37 weeks, body weight 623-2844 g) and the NO concentrations increased significantly with postconceptional age (p < 0.05). Nasal excretion rate, estimated from plateau NO concentrations and sampling flow rate, was 0.10 +/- 0.01 nmol min-1 kg-1 in both groups. We conclude that premature and term newborn infants excrete considerable amounts of NO in the upper airways, with hitherto not fully known functions.

Cross-Sectional Studies↗
PubMed1996

Regional variations in skin perfusion and skin thickness may contribute to varying efficacy of topical, local anaesthetics in neonates.

The national Swedish screening programme for inborn errors of metabolism includes blood sampling from all neonates. Heel lancing has hitherto been the method of choice for these screening tests. Studies have recently been done to find out whether the use of EMLA can alleviate pain caused by heel lancing. EMLA had little, if any effect when applied to the heel of full term babies. Similar results were reported concerning preterm infants. Other authors have found that differences in skin thickness or in skin blood perfusion may influence the effect of EMLA. The aim of this study was to establish whether differences in skin thickness or in skin blood perfusion were present in three regions: the forehead, the dorsum of the hand and the heel. Ten healthy full term neonates were included in the study on skin perfusion. Measurements were made with a laser Doppler flux meter. Twenty-seven healthy full term neonates were included for measurements of skin thickness using a high frequency B-mode ultrasonic meter. The heel skin perfusion was two to three times higher than the skin perfusion at the dorsum of the hand and at the forehead but there was no significant difference when comparing skin thickness of the heel with the dorsum of the hand and the forehead. A rapid clearance of a topically applied local anaesthetic, due to high cutaneous blood flow, may explain why EMLA seems to be of little value when it is applied to the neonatal heel.

Anesthesia, Local↗
PubMed1996

Endogenous nitric oxide in the upper airways of healthy newborn infants.

The endogenous production of nitric oxide (NO) in the upper airways was studied in healthy newborn infants within the first minutes after delivery (N = 2) and at postnatal ages of 1 and 24 h (N = 13). Measurements were made in infants born vaginally or by cesarean section and at various times after the rupture of membranes. Gas was sampled from the nose and pharynx, and NO concentrations were determined by a fast response chemiluminescence analyzer. Sampling from the nose at a constant flow of 20 mL/min gave 0.27 +/- 0.01 parts per million (mean +/- SEM, ppm) of NO, independent of age and mode of delivery (vaginal delivery and cesarean section). Allowing NO to accumulate in the nose for 15-120 s yielded peak concentrations up to 4.6 ppm. A 30% increase was noted between 1 and 24 h of age. We conclude that nasal peak NO concentrations in the ppm range can be demonstrated in the healthy newborn infant within the first hour after birth. Consequently autoinhalation of endogenously produced upper airway NO may play a role in the adaptation of the respiratory system to postnatal life in the human.

Female↗
PubMed1996

Otoacoustic emissions recorded at high rates in patients with confirmed acoustic neuromas.

Otoacoustic emission testing was carried out on 39 patients with confirmed acoustic neuromas, and satisfactory emissions were recorded from the neuroma ear of 59% of them. A comparison of the patients with and without emissions showed no significant differences in low-frequency or high-frequency hearing loss, optimum speech discrimination score, or canal paresis in the affected ear between the two groups. Emissions were recorded at stimulus rates up to 5,000 clicks/s by using the maximum length sequence (MLS) technique. The decrease in the emission amplitude with increase in click rate (rate suppression) was significantly less than the amount that would be expected from normal subjects for several of the neuroma patients. However, one patient showed normal suppression despite having a large neuroma and no measurable hearing. This would suggest that efferent suppression may not be the only mechanism involved.

Acoustic Stimulation↗
PubMed1995

Evaluation of a communication course for new hearing aid users.

A communication course for new hearing aid users, covering explanations of hearing loss and hearing aids, hearing tactics, lipreading and relaxation techniques in three 2 h sessions, was developed. The course was tested on groups of adults fitted with NHS post-aural hearing aids at the Audiology Clinic at the Royal South Hants Hospital. The course content, presentation, length and pace were evaluated by means of a questionnaire given at the end of the last session, and the effects on aid usage, satisfaction and benefit ratings were assessed by pre- and post-fitting questionnaires given to those who attended and to a matched group of control subjects. The course was offered to 41 men and 46 women. The acceptance rate was rather higher for women than for men, but attendance rates were similar for both sexes, men attending 33% and women 36% of the sessions offered. No relationship was observed between age or degree of hearing loss and rates of acceptance and attendance. All those who completed the evaluation questionnaire were satisfied with the content, length, pace and presentation of the course, and considered that it had helped them to understand and cope with their hearing loss. Most (28 out of 31) felt that they would use their aids more as a result of the course. However, their aid usage and ratings of benefit derived from the aids did not differ significantly from those of a matched group of controls who were not offered the course.

Aged↗