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Biomedical subjects

J Weir

Publications and source records attributed to J Weir.

At least 55 records · Page 3Linked to original sources
PubMed1990

A quantitative study of cementum removal with hand curettes.

An in vitro study was conducted to quantitatively measure the depth of root surface removal using curettes of standardized sharpness and with definite stroke number. Extracted periodontally healthy teeth from patients 10 to 15, 16 to 25, and 26 to 40 years old had periodontal ligament remnants removed with dry gauze before being secured in a vertical position during root planing. The force applied to the root surface was measured with a tension load cell. The "bright line" test was used to assess curette sharpness. After histologic processing, the thickness of cementum adjacent to the root defect, the cementum (if any) in the root defect, total amount of cementum removed, and depth of root defect were measured by a microscopic ocular grid. Teeth from each age range were evenly distributed into 6 groups of 10 teeth each. In the majority of teeth from the 20 stroke group through the 70 stroke group, complete cementum removal was observed at the site of planing. However, in some sections from each group, fragments of cementum remained on the root surface. A positive relationship (r/s = 1) was found between the number of strokes and the force applied to the root surface and the mean depth of defect (P less than 0.05). However, an inverse relationship existed between mean force per stroke and mean defect depth (r/s = -.99) such that as mean force per stroke increased, the mean defect depth decreased. As the root surface became smoother with an increasing number of strokes, the forces increased and were more consistent.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Low-field (0.08 T) magnetic resonance imaging of the pancreas: comparison with computed tomography and ultrasound.

Seventy-four patients referred for computed tomography (CT) and ultrasound examination with a presumptive diagnosis of pancreatic disease have been studied using a low-field (0.08 T) magnetic resonance (MR) imaging instrument. A further 50 patients being examined for non-pancreatic disease were also examined to assess the appearances of the normal pancreas. All the MR examinations were performed using an interleaved saturation-recovery/short inversion time (TI) inversion-recovery sequence. Part or all of the pancreas was seen in 96% of normal cases. In inflammatory disease, MR was more accurate than either CT or ultrasound for diagnosis, whilst for the demonstration of pancreatic tumours, MR was found to be no better or worse than either CT or ultrasound. The use of specific T1 measurement for soft-tissue characterization was not useful because of the large overlap in values between normal, inflamed and malignant pancreatic tissue. T1 measurement was found to be useful in differentiating different pathological fluids.

Adult↗
PubMed1988

A ten year survey of superficial mycoses in the Tauranga district, Bay of Plenty.

Between 1 January 1976 and 31 December 1985, 4086 patients living in Tauranga and its environs were examined mycologically. All were suspected of superficial cutaneous mycoses and the majority were referred by general practitioners. A total of 1085 pathogenic fungi were identified, an isolation rate of 27%. The main pathogens identified in order of frequency were--Candida species; Microsporum canis; Trichophyton rubrum; Malassezia furfur; Epidermophyton floccosum; T mentagrophytes var interdigitale. The positivity rate was slightly higher for patients attending the laboratory compared with specimens collected at the surgeries of medical practitioners. Some seasonal variation was noted.

Adolescent↗
PubMed1988

Accelerated increase in aortic diameter in patients treated for lymphoma.

Cytotoxic chemotherapeutic agents, particularly the anthracyclines, are known to be cardiotoxic, but toxic effects on the aorta have not previously been documented. In this study, diameters of ascending and descending thoracic aortae were measured by computerized tomography in 69 patients with lymphoma, before and after first-line treatment with one of 7 different regimes. Minor increases in aortic diameter over the study period due to the aging process were expected. These increases were greater than anticipated in both the ascending and the descending aortae after chemotherapy with CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone) and CVP (cyclophosphamide, vincristine, and prednisolone) regimes. Smaller changes, or changes which were not statistically significant, were noted after MVPP (mustine, vinblastine, procarbazine, and prednisolone), ChlVPP (chlorambucil, vinblastine, procarbazine, and prednisolone), ChlVP (chlorambucil, vincristine and prednisolone), mediastinal radiotherapy, and radiotherapy plus MVPP (MVPP/XRT). Cardiovascular damage associated with certain forms of cytotoxic therapy is not confined to the heart, but also affects the aorta.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

Cancer support groups--who joins and why?

Tak Tent is a cancer support organisation consisting of 14 groups of which 11 are based in Scotland. In 1985, a survey was conducted among those attending the Scottish groups. 146 (79%) of the groups' members completed survey questionnaires. The results showed that Tak Tent's membership mainly comprised cancer patients (36%), relatives of patients (34%) and professionals involved in cancer care (21%). Women outnumbered men 3 to 1 and most of the membership belonged to social classes I, II or III. The groups appeared to be meeting their members' expectations of them to varying degrees. Respondents were satisfied that group membership had allowed them to make new friends, find out more about cancer and meet others facing similar difficulties. They were less certain that participation in a group had enabled them to learn how to cope better with cancer, share their problems with others or provide support for others to the extent they had anticipated.

Adult↗
PubMed1988

Bacillus sporulation gene spo0H codes for sigma 30 (sigma H).

The DNA sequences of the spo0H genes from Bacillus licheniformis and B. subtilis are described, and the predicted open reading frames code for proteins of 26,097 and 25,447 daltons, respectively. The two spo0H gene products are 91% identical to one another and about 25% identical to most of the procaryotic sigma factors. The predicted proteins have a conserved 14-amino-acid sequence at their amino terminal end, typical of sigma factors. Antibodies raised against the spo0H gene product of B. licheniformis specifically react with RNA polymerase sigma factor protein, sigma 30, purified from B. subtilis. We conclude that the spo0H genes of B. licheniformis and B. subtilis code for sigma 30, now known as sigma H.

Amino Acid Sequence↗
PubMed1987

A high carbohydrate diet negates the metabolic effects of caffeine during exercise.

We tested the hypothesis that unrecognized nutritional factors might influence the serum free fatty acid response to caffeine. The time course and extent of the serum free fatty acid response to a fatty meal alone, to caffeine ingestion after a high carbohydrate meal, or to caffeine in combination with either a fatty meal or a high carbohydrate meal (the latter following 3 d of a high carbohydrate diet) were studied in six trained runners. The metabolic response to 120 min of exercise at 75% of maximum oxygen consumption after caffeine ingestion was also studied in runners after a high carbohydrate diet and ingestion of a high carbohydrate meal. Serum free fatty acid levels were highest 3 h after caffeine ingestion alone and were lower following a fatty meal with or without caffeine ingestion (P less than 0.05). The high carbohydrate diet combined with the ingestion of a high carbohydrate meal prevented the expected rise in serum free fatty acid levels following caffeine ingestion. The metabolic response to prolonged submaximal exercise was also not influenced by the ingestion of caffeine by subjects who had eaten a high carbohydrate diet. Nutritional factors, in particular the state of the body carbohydrate stores and the simultaneous ingestion of carbohydrate, influence the response of serum free fatty acid levels to caffeine ingestion.

Adult↗
PubMed1986

Role of computed tomography in assessing "operability" of bronchial carcinoma.

To try to assess the accuracy of predicting "operability" (as defined by local policy) of bronchial carcinoma 300 patients underwent computed tomography of the thorax in a prospective study. The results of 141 patients showed an agreement between computed tomographic and surgical (including pathological) findings in those patients who had received operations. Most of the other patients had more advanced disease than suggested by the findings of computed tomography. A total of 118 patients did not receive operations: in 47 their disease was considered to be inoperable on the basis of computed tomographic findings alone, and this was accepted by the cardiothoracic surgeons after consultation. Thirty two other patients had further evidence of metastatic disease on other investigations. Computed tomography of the thorax should be performed early in the assessment of operability of patients with bronchial carcinoma and before the start of an extensive search for metastatic disease.

Carcinoma, Bronchogenic↗
PubMed1986

Forearm composition and muscle function in trained and untrained limbs.

The influence of a period of training, which lasts for several years, on the proportions of muscle, fat and bone present in the human forearm has been investigated by comparing trained and untrained limbs of nine experienced male tennis players. Ten healthy but untrained males of similar age served as a control group. Computed tomography (CT) scans of the forearm were made at intervals along its length to identify fat, muscle and bone and to calculate the volumes occupied by each of these components. Total forearm volume was greater in the dominant limb compared with the contralateral side in both trained (by 135 +/- 59 cm3, mean +/- SD, P less than 0.001) and untrained subjects (by 41 +/- 45 cm3, P less than 0.02). Forearm muscle volume was also greater in dominant limbs of trained (by 117 +/- 52 cm3, P less than 0.001) and untrained by 35 +/- 41 cm3, P less than 0.025) subjects. Muscle accounted for 75.4 +/- 2.7% of the total volume in the dominant arm of trained subjects compared with 71.4 +/- 4.2% in the control group (P less than 0.05). There was a greater proportion of muscle (P less than 0.05) and a smaller proportion of fat (P less than 0.001) in the trained limb compared with the contralateral limb of the same subjects. No differences in proportions of fat, muscle and bone were observed in dominant and non-dominant limbs of the control subjects. Trained subjects were able to exert a greater isometric force with the dominant limb (549 +/- 76N) than with the non-dominant limb (496 +/- 48N; P less than 0.005). There was no difference in grip strength between the arms of the untrained group (dominant: 516 +/- 107N; non-dominant: 491 +/- 91N). The ratio of strength to muscle volume was, however, the same in dominant and non-dominant arms of both groups of subjects.

Adult↗
PubMed1986

Effect of age and blood pressure on aortic size and stroke distance.

The diameters of the ascending and descending aorta at the level of the carina were measured from computerised tomograms in 200 adults without cardiac or aortic disease. At all ages the ascending aorta had a greater cross sectional area than the descending aorta, and both areas increased significantly with age. The increase was proportionately greater in the descending than in the ascending aorta and the percentage changes were similar in males and females, the latter having a smaller mean descending aortic diameter. The extent of the increase in cross sectional area of the aorta is sufficient to explain the observed fall of stroke distance that occurs with age. The effect of changing blood pressure on aortic cross sectional area, and hence the relation between stroke distance and stroke volume, was calculated from published data on aortic compliance at different ages. Assuming constant peripheral resistance, stroke distance would change by 34, 82, and 94% for a 100% change of stroke volume at age 20, 50, and 80 respectively. At age 80 the aorta behaves like a rigid pipe but at age 20 its elasticity is such that constancy of aortic size cannot be assumed.

Adult↗
PubMed1984

The relative proportions of fat, muscle and bone in the normal human forearm as determined by computed tomography.

Computed tomography has been used to establish the proportions of fat, muscle and bone present in the normal human forearm. Subjects were healthy young volunteers, eight males and eight females. A series of six cross-sectional scans at right angles to the long axis of the forearm was obtained, the scans being made at equidistant intervals between the olecranon process and the ulnar styloid. The volumes occupied by fat, muscle and bone were calculated for the complete forearm. Total forearm volume calculated by this method agreed closely with that measured by water displacement. For the male subjects, forearm composition was 72.1 +/- 4.4% muscle (mean +/- SD), 15.0 +/- 5.3% fat and 12.9 +/- 1.2% bone. Female forearms had less muscle (P less than 0.001) and more fat (P less than 0.001) than those of the male subjects: 58.5 +/- 4.0% muscle, 29.3 +/- 5.0% fat and 12.3 +/- 1.4% bone. Forearm muscle volume was significantly correlated (r = 0.75; P less than 0.05) with lean body mass in the male subjects; the range of values for lean body mass in the female subjects was too small to permit calculation of the equivalent relationship. Forearm fat content, as a percentage of total volume, was proportional to whole body fat content as estimated from skinfold thickness (males, r = 0.84; P less than 0.01; females, r = 0.77; P less than 0.05). These relationships enable estimates of the volumes of forearm tissue components to be derived from anthropometric measurements.

Adipose Tissue↗
PubMed1984

Bacillus subtilis spo0H gene.

A 2.8-kilobase fragment of the Bacillus subtilis chromosome containing a functional spo0H gene was cloned by using a modification of the helper system described by T. Gryczan and co-workers (T. Gryczan, S. Contente, and D. Dubnau, Mol. Gen. Genet. 177:459-467, 1980). The chromosomal segment specifically complements spo0H mutations in recE4 strains and when integrated into the chromosome of Rec+ strains maps in the spo0H region of the B. subtilis genome. A deletion within the transcribed region of the cloned spo0H gene was constructed which abolishes its spo0H+-complementing activity. DNA sequences containing this deletion were introduced into a B. subtilis Rec+ strain containing the spo0H75 mutation. The absence of recombination between the deletion and the spo0H mutation indicates that both reside in the same gene. There is homology between the B. subtilis spo0H gene and a 1.2-kilobase chromosomal fragment from Bacillus licheniformis which also complements B. subtilis spo0H mutations. In vivo transcription mapping experiments have shown that the B. subtilis spo0H gene is transcribed during vegetative growth as well as during sporulation.

Bacillus subtilis↗
PubMed1984

Muscle strength and cross-sectional area in man: a comparison of strength-trained and untrained subjects.

This study has examined muscle strength and cross-sectional area in a group of 35 healthy untrained male subjects and 8 subjects who had been engaged in a strenuous weight-training programme. The maximum voluntary knee extension force which could be produced by the untrained subjects was 742 +/- 100 N (mean +/- SD). The trained subjects could produce a significantly (p less than 0.001) greater force (992 +/- 162 N). Cross-sectional area of the knee-extensor muscle group was 81.6 +/- 11.8 cm2 in the untrained subjects and 104.1 +/- 12.3 cm2 in the trained subjects (p less than 0.001). In the untrained subjects, a significant correlation existed between strength and muscle cross-sectional area (r = 0.56, p less than 0.001). In the same group of subjects, there was a significant inverse relationship between muscle cross-sectional area and the ratio of strength to cross-sectional area (r = 0.55, p less than 0.001). The mean ratio of strength to cross-sectional area was 9.20 +/- 1.29 for the untrained group whereas for the trained group this ratio was 9.53 +/- 1.01. It is suggested that the inverse relationship between strength per unit cross-sectional area and cross-sectional area results in part from an increased angle of pennation in the larger muscles.

Adult↗
PubMed1984

Positive T wave overshoot as a sign of ventricular enlargement.

A consecutive series of 86 patients with an inverted T wave showing terminal positivity (overshoot) of a specific pattern in the resting electrocardiogram were studied. Patients with bundle branch block or electrocardiographic evidence of acute infarction and those taking digoxin or a similar drug were excluded. In 67 patients the heart was examined by echocardiography and in a further two by direct inspection. Sixty six of the 69 patients had an abnormal thickness of the left (or right) ventricle or a calculated left ventricular mass greater than 200 g. Seven of the patients examined by echocardiography had clinically pure ischaemic heart disease; all showed evidence of left ventricular enlargement. In only 39 of the 63 patients with anatomical evidence of left ventricular hypertrophy or dilatation did the electrocardiogram satisfy the standard voltage criterion of left ventricular hypertrophy. In the absence of acute infarction, bundle branch block, or digitalisation positive T wave overshoot of the pattern described is a sign of increased ventricular mass.

Adolescent↗