PubMed Health⌕ Search

Biomedical subjects

J M Hardy

Publications and source records attributed to J M Hardy.

11 recordsLinked to original sources
PubMed1993

Respiratory gas exchange indices used to detect the blood lactate accumulation threshold during an incremental exercise test in young athletes.

The time course of changes in blood lactate concentration and ventilatory gas exchange was studied during an incremental exercise test on a cycle ergometer to determine if the lactate accumulation threshold (LT2) could be accurately estimated by the use of respiratory indices (VT2) in young athletes. LT2 was defined as the starting point of accelerated lactate accumulation. VT2 was identified by the second exponential increase in VE and the ventilatory equivalent for O2 uptake with a concomitant nonlinear increase in the ventilatory equivalent for CO2 output. Twelve trained subjects, aged 18-22 years, participated in this study. The initial power setting was 30 W for 3 min with successive increases of 30 W every minute except at the end of the test when the increase was reduced. Ventilatory flow (VE), oxygen uptake (VO2), carbon dioxide output (VCO2), and ventilatory equivalents of O2 and CO2 were determined during the last 30 s of every minute. Venous blood samples were drawn at the end of each stage of effort and analysed enzymatically for lactate concentration. After each test, LT2 and VT2 were determined visually by two investigators from the graphic results using a double-blind procedure. The results [mean (SEM)] indicate no significant difference between LT2 and VT2 expressed as VO2 [43.98 (1.70) vs 44.93 (2.39) ml.min-1 x kg-1], lactataemia [4.01 (0.28) vs 4.44 (0.37) mM.l-1], or heart rate [171 (3.36) vs 173 (3.11) min-1]. In addition, strong correlations were noted between the two methods for VO2 (r = 0.90, P < 0.001), lactataemia (r = 0.75, P < 0.01), and heart rate (r = 0.96, P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Age and training effects on the lactate kinetics of master athletes during maximal exercise.

To study the effects of age and training on lactate production in older trained subjects, the lactate kinetics of highly trained cyclists [HT, n = 7; 65 (SEM 1.2) years] and control subjects with low training (LT, n = 7) and of similar age were compared to those of young athletes [YA, n = 7; 26 (SEM 0.7) years], during an incremental exercise test to maximum power. The results showed that the lactacidaemia at maximal oxygen uptake (VO2max) was lower for HT than for LT (P < 0.05) and, in both cases, lower than that of YA (P < 0.001). The respective values were HT: 3.9 (SEM 0.51), LT: 5.36 (SEM 1.12), and YA: 10.3 (SEM 0.63) mmol.l-1. At submaximal powers, however, the difference in lactacidaemia was not significant between HT and YA, although the values for lactacidaemia at VO2max calculated per watt and per watt normalized by body mass were significantly lower for HT (P < 0.001) and LT (P < 0.02). These results would indicate that the decline in power with age induced a decline in lactacidaemia. Yet this loss in power was not the only causative factor; indeed, our results indicated a complementary metabolic influence. In the older subjects training decreased significantly the lactacidaemia for the same submaximal power (P < 0.01) and from 60% of VO2max onwards (P < 0.05); as for YA it postponed the increase and accumulation of lactates. The lactate increase threshold (Thla-,1) was found at 46% VO2max for LT and at 56% VO2max for HT.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

The Sequoia circular fixator for limb lengthening.

With the Sequoia fixator, lengthenings can be achieved based on the clinical facts of the case. The device is a modular apparatus that can perform corrections in several planes, and, if necessary, in a septic environment. In our opinion, a "lengthener surgeon" is one who can foresee problems and take appropriate steps to prevent them. Likewise, the surgeon must act as the coordinator of an entire team. A successful lengthening is 5% surgery and 95% postoperative nursing and physiotherapy care. In the future, a number of changes will simplify postoperative management: 1. Composite carbon rings will make the frames radiolucent and one third lighter than those made of stainless steel. Automatic tensioners will help maintain steady tension on the wires. 2. Digital analysis of the callus will provide norms of consolidation, allowing faster fixator removal and conversion to an orthosis. 3. Incorporating the foot in the frame to overcome equinus will eliminate the need for tenotomy. We believe that monolateral and ring fixators can work together in certain locations. That is why we proposed, at the 18th Societé Internationale de Chirurgie Orthopédique et Traumatologique meeting, a combined monolateral-ring construct that can be used for lengthening throughout the proximal femoral metaphysis.

Adolescent↗
PubMed1980

[Ectopic openings of the common bile duct. A contribution to the physiological study of the sphincter of Oddi (author's transl)].

Two cases of ectopic openings of the common bile duct are reported. In one case there was a congenital short duct opening into DI, the presence of a spontaneous duodenobiliary reflux due to absence of the papilla being demonstrated by clinical and radiological examinations. The other patient had a long duct opening into D3 and no duodenobiliary reflux, but with an intact sphincter of Oddi explored in detail by means of combined choledochoduodenal manometry. These two cases demonstrate that the duodenal wall has only a moderate effect in preventing duodenobiliary reflux. The essential element is the sphincter of Oddi: if present, there is no reflux, if absent, reflux occurs.

Adult↗
PubMed1978

Progress of infants fed Karitane Milk Food compared with those on breast or homogenised milk.

A study was made of three groups of babies, one breast fed, one having Karitane Milk Food, the third homogenised milk. Blood sodium and urea were measured in the neonatal period. The urea levels were significantly higher in babies having homogenised milk compared with those fed Karitane or breast milk. Haemoglobin was measured in the neonatal period, and at 3, 6, 10 1/2 and 18 months. At six months, haemoglobin levels were significantly higher in Karitane milk fed than in homogenised milk fed babies. Serum cholesterol and triglyceride were measured in cord blood, and at 6 and 18 months of age. Serum triglyceride levels in babies on Karitane Milk Food were significantly higher than those on homogenised milk. Increments in weight, height and head circumference were compared. Karitane milk fed babies gained significantly more weight than breast fed between three and six months of age.

Animals↗
PubMedDate not supplied

Osteoplastic frontal sinusotomy: an analysis of 250 operations.

The operative approach and findings of 250 osteoplastic frontal sinusotomy operations performed from 1956 through 1972 at the Massachusetts Eye and Ear Infirmary are reviewed. Indications for surgery were symptomatic and/or complicated disease of the frontal sinus, including primary chronic sinusitis and osteoma or trauma with or without associated infection. Immediate postoperative complications were minor. Follow-up of at least three years was obtained in 83% of the patients, and 93% of these have no significant symptoms to date. A distressing problem of persistent postoperative frontal pain is discussed in detail. Revision surgery has been performed in 6% of patients due to recurrent frontal sinus infection. The reasons for failure are anlyzed, and recommendations are made to minimize the possibility of recurrence.

Adolescent↗