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Biomedical subjects

N Prasad

Publications and source records attributed to N Prasad.

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

Correlations between condylar characteristics and facial morphology in Class II preadolescent patients.

The aim of this retrospective study was to determine correlations between condylar characteristics measured from preorthodontic tomograms of preadolescents and their facial morphologic characteristics. The sample consisted of 136 patients displaying a Class II malocclusion, a vertical or horizontal skeletal growth tendency, and ranging in age between 10 years 0 months and 12 years 6 months for males and 9 years 0 months and 11 years 6 months for females. Two groups were established: the vertical group had 68 patients, 36 males and 32 females, (average pretreatment age, 11 years 0 months); the horizontal group also had 68 patients, 29 males and 39 females, their average pretreatment age was 10 years 9 months. The central cut of axially corrected lateral tomograms of the left and right temporomandibular joints for each group was randomized, blinded, and traced for condyle/fossa measurements including: anterior, superior and posterior joint space; condylar head and posterior condylar ramus inclination; condylar neck width; and condylar shape and condylar surface area. A logistic discriminant analysis with significance values set at p < 0.05 was used to determine the most reliable condylar characteristics to predict facial morphology. A cluster analysis was completed on the significant variables to form three clusters. Numeric ranges separating these clusters were then calculated. Chi-square tests measures of association were computed for significant variables and tested for associations between facial morphologic characteristics. Condylar head inclination and superior joint space proved to be significantly correlated to facial morphology (p values ranged from 0.010 to 0.018). Patients with vertical facial morphologic characteristics displayed decreased superior joint spaces and posteriorly angled condyles. Increased superior joint spaces and anteriorly angled condyles were significantly correlated to patients with a horizontal facial morphology. No significant correlations between the other condylar characteristics and facial morphology were determined.

Analysis of Variance↗
PubMed1997

Anthropometric data of Indian farm workers--a module analysis.

Anthropometric data of Indian farm workers have been compared with various other ethnic groups. The analysis indicates that there is a significant difference in the body dimensions which must be taken into account in designing farm equipment.

Agriculture↗
PubMed1997

Cephalometric landmarks identification and reproducibility: a meta analysis.

To assess the magnitude of cephalometric landmarks identification error, we performed a Meta analysis on six pertinent studies. We outline the procedures used to compare and integrate the findings of these-studies. The results are a measure of systematic and random errors involved when locating landmarks on lateral head films. They are presented as standard mean errors and 95% confidence intervals for the repeatability and reproducibility of 15 cephalometric landmarks commonly used in growth analysis.

Cephalometry↗
PubMed1997

Influence of the angiotensin converting enzyme I/D gene polymorphisms on left ventricular diastolic filling in patients with essential hypertension.

BACKGROUND: An insertion/deletion (I/D) polymorphism in the angiotensin converting enzyme (ACE) gene accounts for 50% of the variance in serum ACE activity. ACE is responsible for the generation of angiotensin II, which not only has pressor and mitogenic activities but also exerts effects on left ventricular diastolic performance. OBJECTIVE: To investigate the contribution of genetic polymorphisms at the ACE gene to the development of diastolic functional abnormalities in 100 patients with essential hypertension. METHODS AND RESULTS: The left ventricular mass (LVMI) of each patient was assessed echocardiographically. We calculated peak and integral early:late left ventricular diastolic filling ratios (E:AP, and E:AI, respectively) and determined the ACE genotype from leukocyte DNA. There was no significant difference in age, sex, blood pressure and LVMI among genotype groups. Analysis of covariance modelled for indices of diastolic function, adjusted for age, sex, heart rate and LVMI, demonstrated that the E:AP interacted with age (P < 0.0001), heart rate (P < 0.001) and ACE genotype (P = 0.018). Similarly, the E:AI interacted with age (P < 0.001), heart rate (P = 0.025) and ACE genotype (P = 0.047). There was a strong correlation between the E:AP and the LVMI for the DD group (r = -0.81, P < 0.0001) but not for the ID (r = -0.03, P = 0.83) and II (r = -0.23, P = 0.23) groups. CONCLUSIONS: These findings suggest that that the I/D polymorphism of the ACE gene influences the relationship between left ventricular mass and echocardiographic left ventricular diastolic filling abnormalities in patients with essential hypertension.

Adult↗
PubMed1997

Safe withdrawal of monotherapy for hypertension is poorly effective and not likely to reduce health-care costs.

OBJECTIVE: To carry out a population-based evaluation of withdrawal of treatment in primary care using repeated ambulatory blood pressure monitoring (ABPM) assessment to avoid subjecting patients to prolonged periods of excess risk. METHOD: Patients from two community practices (total population 11 034 patients) being administered monotherapy for hypertension, were identified and invited to participate. Subjects were withdrawn from treatment if they had no significant co-morbidity and daytime ABPM blood pressure was < or = 150/90 mmHg. Antihypertensive therapy was restarted if daytime ABPM blood pressure was > 150/90 mmHg during weeks 4, 8, 12, 26, 39 and 52. RESULTS: Of 126 eligible patients 53 had a co-morbidity and 37 declined to participate. Of the 36 patients who entered the study 10 were excluded because they had elevated ABPM blood pressures during treatment and one because they had echocardiographic left ventricular hypertrophy. Of the 25 patients from whom monotherapy was withdrawn, we restarted treatment of 19 before week 52. If clinic blood pressure monitoring had been used instead of ABPM, different decisions would have been taken in eight of 25 cases. The costs of the ABPM-determined withdrawal of treatment programme were greater than the expected savings in drug costs, even assuming that all six patients from whom treatment was withdrawn remained without treatment for a further 9 years. This conclusion was not sensitive to reducing the number of ABPM measurements and to inflation in study-drug costs. However, if all patients had been treated with the most expensive drug, then even the full ABPM programme could have saved money within 9 years. CONCLUSIONS: Antihypertensive therapy could be withdrawn from only a small proportion of patients in the community on the basis of ABPM. The costs of the programme are likely to exceed savings unless the cost of drugs administered is substantially higher than that observed in this study.

Aged↗
PubMed1997

Comparison of immunomodulation by cyclosporin A and azathioprine on pancreatic xenograft survival.

Prolonged survival of pancreatic xenografts in the muscles of diabetic rabbits under the immunomodulation of cyclosporin A and azathioprine was achieved. The mean graft survival time (as assessed by euglycemic status and histopathological findings) in Group A (azathioprine treated) was 36 days, in Group B (cyclosporin A treated) it was 69 days, and the difference was significant (p < 0.001). Adequate immunosuppression helps the pancreatic xenograft to normalize the blood glucose level (BGL) by prolonging its survival time. Our study demonstrates that xenotransplanted islet cells in a natural environment (pancreatic tissue in the form of thin slices) survive and function adequately in immunosuppressed recipients, and addition of cyclosporin A significantly prolongs survival of the xenograft. This discordant xenotransplantation model may be useful for future xenotransplantation studies.

Adjuvants, Immunologic↗
PubMed1997

Use of fax facility improves decision making regarding thrombolysis in acute myocardial infarction.

BACKGROUND: Electrocardiography is the fundamental investigation for decision making regarding thrombolytic treatment in acute myocardial infarction (MI). Increasing the accuracy of ECG analysis by input from consultant staff may assist in management decisions in patients with suspected MI. AIMS: To evaluate a system whereby out of hours ECGs can be faxed to the consultant to aid in decision making regarding thrombolytic treatment. METHODS: 112 patients with suspected MI were assessed on admission by the senior house officer (SHO) who faxed to a cardiology consultant the ECG trace and a predesigned form with information on: clinical assessment of the patient; interpretation of the ECG; and views regarding administration of thrombolytic treatment including choice of agent. The consultant reviewed the information and communicated his views to the SHO. Subsequent diagnosis was recorded in all patients and the forms were analysed in regard to areas of agreement and disagreement between the SHO and the consultant. RESULTS: A diagnosis of MI was confirmed in 52 of the 112 patients (46.4%). The consultant agreed with the SHO's decision on thrombolysis in 98 patients (87.5%). The reason for disagreement in the remaining 14 patients (12.5%) was SHO misinterpretation of the ECG (10 patients) and clinical assessment (four patients). Eight patients were saved unnecessary thrombolytic treatment and four received it when they otherwise would not have. Additionally the choice of thrombolytic agent was changed in six patients from streptokinase to tissue plasminogen activator. CONCLUSION: The use of fax machine assists in decision making with regard to thrombolytic treatment and provides support to junior doctors in what can be a difficult, yet critical decision.

Adult↗
PubMed1997

Direct admission to the coronary care unit by the ambulance service for patients with suspected myocardial infarction.

BACKGROUND: Direct access to the coronary care unit (CCU) for general practitioner (GP) referred cases of suspected acute myocardial infarction (AMI) (fast track admission) substantially reduces the time to thrombolysis. Until now, this policy has been confined to GP referrals. OBJECTIVES: To determine the time taken to admission to CCU under the fast track policy (ambulance referrals and GP referrals) and the time taken to start administration of thrombolytics (ambulance referrals, GP referrals, and accident and emergency referrals). METHODS: Fast track admission policy was extended to include referrals from ambulance personnel who respond to emergency service calls. Ambulance personnel referred cases were also examined to see if they were referred appropriately to the CCU. RESULTS: 100 ambulance personnel referrals and 260 GP referrals to CCU with chest pain were studied. Forty accident and emergency referrals who had AMI requiring thrombolysis were also studied. In the ambulance referred group the time to admission from phone call was a median of 10 minutes (range 2 to 45), a saving of 30 minutes compared with GP referrals (median 40 minutes, range 2 to 217). The median diagnostic electrocardiogram (ECG) to thrombolysis time was longer in the accident and emergency referrals with AMI than either ambulance referrals or GP referrals admitted under the fast track policy. Diagnostic ECG to thrombolysis time: accident and emergency 50 minutes (range 15 to 385); ambulance referrals median 33 minutes (range 6 to 69); GP referrals median 29.5 minutes (range 5 to 110 minutes); (p = 0.056 accident and emergency compared with ambulance referrals, p < 0.002 accident and emergency compared with GP referrals). Of 100 ambulance referrals 52 patients exhibited symptoms suggestive of ischaemic heart disease (confirmed AMI, unstable angina, and angina) and a further 18 patients were required to stay in CCU for other cardiac problems. Thus a total of 70 (70%) were considered appropriate compared with 155 of 260 (55.8%) GP referred cases. CONCLUSIONS: Extending the fast track admission policy to ambulance personnel reduces delay to admission for patients with suspected MI without adversely affecting the appropriateness of admissions.

Adult↗
PubMed1997

Modulation of autoimmune responses by intravenous immunoglobulin (IVIg).

Significant progress has been made in understanding the mechanisms by which intravenous immunoglobulins (IVIg) exert immunomodulatory effects in the treatment of autoimmune diseases. A unique property of immunoglobulins is the diversity of variable (V) regions. The evidence discussed in this communication supports our notion that the diversity of V regions in IVIg preparations is a determining factor for the anti-inflammatory substitutive and immunomodulatory functions of IVIg therapy. We have demonstrated the presence in IVIg, of anti-idiotypic antibodies directed against various autoantibodies. The ability of IVIg to interact through V regions with complementary V regions of antibodies and antigen receptors as well as with relevant soluble and surface molecules provides the basis for inducing the selection of immune repertoires. The study of the mechanisms by which IVIg mediates selection of autoreactive repertoires is essential for our understanding of the mechanisms underlying the emergence of pathological autoimmunity and of the physiological role of natural antibodies in the establishment and maintenance of tolerance to self and homeostasis of autoreactivity in healthy individuals.

Animals↗
PubMed1997

Ketorolac tromethamine in the maintenance of intraoperative mydriasis.

BACKGROUND AND OBJECTIVE: Mydriatics and antiprostaglandins are routinely applied preoperatively to facilitate the aspiration of cortical material during extracapsular cataract surgery and to prevent intraoperative miosis. Unfortunately, the ideal antiprostaglandin has yet to be introduced. This study represents the first prospective, case-controlled, randomized, masked, clinical trial comparing the efficacy of oral ketorolac tromethamine (KT) with the efficacy of topical flurbiprofen sodium (FS) and a placebo (normal saline) in maintaining intraoperative mydriasis without adrenaline in the irrigation solution. PATIENTS AND METHODS: Sixty-three patients, undergoing extracapsular cataract extraction with posterior chamber intraocular lens implantation, were randomly divided into three equal groups. Group 1 received 20 mg of oral KT 2 hours prior to surgery, group 2 received 0.03% FS topical solution at the recommended dosage, and group 3 received topical normal saline in a regimen identical to that of group 2. Identical mydriatics were used in both groups. The patients' pupils were measured at five stages of surgery. RESULTS: The mean pupillary diameters at each surgical stage were greater in group 1 than in group 2; however, the difference was not statistically significant. The pupils in group 3 were significantly smaller than those of group 1 or group 2 (P < .05). No systemic toxicity to KT was observed. Moreover, the need for additional postoperative analgesics was significantly greater in groups 2 and 3. CONCLUSIONS: Oral KT is safe, convenient, and as effective as topical FS, and has the added advantage of reducing postoperative pain.

Administration, Oral↗
PubMed1996

The white-coat response in ambulatory blood pressure monitoring: elimination and attenuation.

BACKGROUND: The white-coat response can be identifiede on ambulatory blood pressure (ABP) monitoring (ABPM) and it is seen for around 2 h if the ABPM period is started in the hospital. The white-coat response to ABPM can be calculated by subtracting the 25th h ABP from the 1st h ABP; this eliminates any effect of the 24 h variation in blood pressure. METHODS: In this report we have examined whether the white-coat response is due to the environment alone or partly due to the ABPM machine (study 1). We also examined whether the white-coat response found with ABPM attenuates on repeated visits (study 2). In study 1 we started ABPM at the subject's home 3 h after an initial explanation and measurement of blood pressure in the hospital (hospital blood pressure) and examined the white-coat response (measured as the 1st h - 25th h ABP). In study 2 we performed ABPM on three occasions starting ABPM in the hospital and examined the magnitude of the white-coat response at each visit. RESULTS: In study 1 the hospital blood pressure was significantly higher than the hourly mean blood pressure at the same time of day on the following day. There was no significant difference between the 1st and 25th hourly means or the 2nd and 26th hourly means after the monitoring had been restarted at home. In study 2, the 1st and 25th mean hourly ambulatory blood pressures showed a significant reduction in the 1st h blood pressure over the three visits whereas the 25th h blood pressure was similar. The 1st h - 25 h systolic ambulatory blood pressure was significantly reduced ( P = 0.025) whereas the reduction in diastolic ambulatory blood pressure did not attain statistical significance (P = 0.182). CONCLUSION: The ABPM device itself does not cause the white-coat response seen on ABPM. This response appears to be related to the environment in which ABPM is commenced and can be eliminated by calculating the ABP beginning 3 h after the subject has left the hospital environment. Attenuation of this response is seen on repeated ABPM.

Journal Article↗