Biomedical subjects

N D Duncan

Publications and source records attributed to N D Duncan.

36 records · Page 2Linked to original sources

PubMed1999

Postsplenectomy course in homozygous sickle cell disease.

OBJECTIVE: To determine whether children with homozygous sickle cell (SS) disease and splenectomy are at greater risk of death, overwhelming septicemia, or other complications. METHODS: A total of 130 patients with SS treated by splenectomy (46 recurrent acute splenic sequestration, 84 chronic hypersplenism) over a 22.5-year period at the Sickle Cell Clinic of the University Hospital of the West Indies, Kingston, Jamaica, were compared with a control group matched for sex, age, and duration of follow-up in a retrospective review. Deaths and bacteremias were examined over the whole study period. Painful crises, acute chest syndromes, and febrile episodes were compared in the 90 patients completing 5 years of postsplenectomy follow-up. FINDINGS: Mortality and bacteremic episodes did not differ between the splenectomy and control groups. Painful crises were more common in the splenectomy group than in the control group (P =.01) but did not differ between splenectomy indications. Acute chest syndrome was more common in the splenectomy group than in the control group (P <.01) and was more common in the acute splenic sequestration group than in the hypersplenism group (P =.01). Febrile events did not differ between the groups or between the indications for splenectomy. CONCLUSION: Splenectomy does not increase the risk of death or bacteremic illness in patients with SS disease and, if otherwise indicated, should not be deferred for these reasons.

Adolescent↗

PubMed1999

Performance and muscle fiber adaptations to creatine supplementation and heavy resistance training.

PURPOSE: The purpose of this study was to examine the effect of creatine supplementation in conjunction with resistance training on physiological adaptations including muscle fiber hypertrophy and muscle creatine accumulation. METHODS: Nineteen healthy resistance-trained men were matched and then randomly assigned in a double-blind fashion to either a creatine (N = 10) or placebo (N = 9) group. Periodized heavy resistance training was performed for 12 wk. Creatine or placebo capsules were consumed (25 g x d(-1)) for 1 wk followed by a maintenance dose (5 g x d(-1)) for the remainder of the training. RESULTS: After 12 wk, significant (P < or = 0.05) increases in body mass and fat-free mass were greater in creatine (6.3% and 6.3%, respectively) than placebo (3.6% and 3.1%, respectively) subjects. After 12 wk, increases in bench press and squat were greater in creatine (24% and 32%, respectively) than placebo (16% and 24%, respectively) subjects. Compared with placebo subjects, creatine subjects demonstrated significantly greater increases in Type I (35% vs 11%), IIA (36% vs 15%), and IIAB (35% vs 6%) muscle fiber cross-sectional areas. Muscle total creatine concentrations were unchanged in placebo subjects. Muscle creatine was significantly elevated after 1 wk in creatine subjects (22%), and values remained significantly greater than placebo subjects after 12 wk. Average volume lifted in the bench press during training was significantly greater in creatine subjects during weeks 5-8. No negative side effects to the supplementation were reported. CONCLUSION: Creatine supplementation enhanced fat-free mass, physical performance, and muscle morphology in response to heavy resistance training, presumably mediated via higher quality training sessions.

Adaptation, Physiological↗

PubMed1999

Necrotising enterocolitis: a management protocol for developing countries.

28 cases of necrotising enterocolitis (NEC) comprising 11 term and 17 preterm patients were diagnosed between January 1990 and December 1995 at the University Hospital of the West Indies (UHWI). Treatment was in accordance with a management protocol which emphasised aggressive screening of potential cases, early laparotomy for bowel perforation and primary anastomosis after small bowel resection. There were three deaths among the 13 cases of bowel perforation. Centres in developing countries can achieve rates of survival comparable to those in the developed world in babies with NEC weighing over 1000 grams by adopting the UHWI management protocol.

Anastomosis, Surgical↗

PubMed1999

Trauma aetiology and cost in the Accident and Emergency Unit of the University Hospital of the West Indies.

Trauma accounted for 37% of 22,311 patients seen in the Accident and Emergency Unit (A&E Unit) at the University Hospital of the West Indies (UHWI) during 1996. Thirty-nine per cent of injuries were intentional and 18% were due to motor vehicle accidents. Knives, machetes and rocks accounted for 75% of the injuries compared with 5% for gunshot wounds. Passengers were injured in about 40% of motor vehicle accidents and pedestrians in 19%. The admission rate was 16% and the orthopaedic clinic received 75% of the patients referred to specialist clinics. Victims of motor vehicle accidents made up a greater proportion of admissions (24%) than those of intentional violence (13%). The average cost of caring for each patient in the A&E unit was US$70 resulting in an annual cost of US$578,000.

Adolescent↗

PubMed1999

Alcohol, cannabis and cocaine usage in patients with trauma injuries.

Sera from 111 patients with trauma injuries, who presented to the Accident and Emergency Unit (A&E), University Hospital of the West Indies, during a 3-month period, were screened for blood alcohol. Urine specimens were analysed for metabolites of cannabis and cocaine. Sixty-two per cent (62%) of patients were positive for at least one substance and 20% for two or more. Positivity rates were as follows: cannabis (46%), alcohol (32%) with 71% of these having blood alcohol levels (BAC) greater than 80 mg per decilitre; cocaine (6%). Substance usage was most prevalent in the third decade of life. The patients who yielded a positive result were significantly younger than those who were negative. There was no significant difference in age or substance usage between the victims of interpersonal violence or road traffic accidents. In the group designated "other accidents", patients were significantly older and had a lower incidence of substance usage than the other two groups. Cannabis was the most prevalent substance in all groups. Fifty per cent (50%) and fifty-five per cent (55%) of victims of road accidents and interpersonal violence, respectively, were positive for cannabis compared with 43% and 27% for alcohol, respectively. There was no significant difference in Hospital Stay or Injury Severity Score between substance users and non-users.

Adolescent↗

PubMed1998

CT appearances of the Rapunzel syndrome: an unusual form of bezoar and gastrointestinal obstruction.

The CT appearances of an unusual type of trichobezoar which causes the Rapunzel syndrome are described. This syndrome is characterized by intestinal obstruction secondary to a bezoar possessing a tail which extends to or beyond the ileo-cecal valve. Most cases of bezoar are diagnosed with plain films or barium meal, but CT may be requested in patients who present with abdominal masses. The Rapunzel syndrome may be diagnosed with a combination of the CT findings and the history.

Bezoars↗

PubMed1998

Adaptations in rat skeletal muscle following long-term resistance exercise training.

The purpose of this investigation was to determine whether long-term, heavy resistance training would cause adaptations in rat skeletal muscle structure and function. Ten male Wistar rats (3 weeks old) were trained to climb a 40-cm vertical ladder (4 days/week) while carrying progressively heavier loads secured to their tails. After 26 weeks of training the rats were capable of lifting up to 800 g or 140% of their individual body mass for four sets of 12-15 repetitions per session. No difference in body mass was observed between the trained rats and age-matched sedentary control rats. Absolute and relative heart mass were greater in trained rats than control rats. When expressed relative to body mass, the mass of the extensor digitorum longus (EDL) and soleus muscles was greater in trained rats than control rats. No difference in absolute muscle mass or maximum force-producing capacity was evident in either the EDL or soleus muscles after training, although both muscles exhibited an increased resistance to fatigue. Individual fibre hypertrophy was evident in all four skeletal muscles investigated, i.e. EDL, soleus, plantaris and rectus femoris muscles of trained rats, but muscle fibre type proportions within each of the muscles tested remained unchanged. Despite an increased ability of the rats to lift progressively heavier loads, this heavy resistance training model did not induce gross muscle hypertrophy nor did it increase the force-producing capacity of the EDL or soleus muscles.

Adaptation, Physiological↗

PubMed1998

Resistance training and elite athletes: adaptations and program considerations.

The skepticism surrounding the potential benefits of resistance exercise training prevalent just decades ago has evolved over the years to an understanding of the integral nature muscular overload plays in the training programs for athletes. The science of training elite athletes is progressing rapidly, as insights into the physiological adaptations resulting from varying program configurations become available. Resistance training impacts several body systems, including muscular, endocrine, skeletal, metabolic, immune, neural, and respiratory. An understanding and appreciation of basic scientific principles related to resistance training is necessary in order to optimize training responses. Careful selection of the acute program variables in a workout to simulate sports-specific movements is required for optimal transfer of gains made in training to competition. Thus, whether athletes require predominantly eccentric, isometric, slow-velocity, or high-velocity strength or power in their athletic event will dictate the time commitment to each component and form the basis for designing individual workouts. Program variation over a training period is essential to maximize gains and prevent overtraining.

Adaptation, Physiological↗

PubMed1998

Hydrostatic reduction of acute intussusception. A prospective study.

Data were collected prospectively on 57 Jamaican children presenting with 62 episodes of acute intussusception over a two year period, for whom operative and hydrostatic methods of reduction were employed. 31 (54%) of 57 episodes were reduced successfully using barium (42), saline (11) and air (4) hydrostatically. Among the 31 other episodes, 15 had ileo-colic intussusception, seven caeco-colic, six ileo-ileo-colic and one ileo-ileal. Two patients had spontaneous reduction discovered at surgery. There were two episodes of barium hydrostatic perforation of the colon leading to death in one patient. Hydrostatic reduction is recommended as the first therapeutic option for acute intussusception because it spares the patient a major operative procedure when successful.

Acute Disease↗

PubMed1997

Torsion of an intra-abdominal testicle in a neonate. Case report and review of the literature.

The thirty-ninth reported case of torsion of an intra-abdominal testicle is described in a neonate. The gonad was excised as is recommended because of the high incidence of malignancy (60% of 37 cases). Torsion of an intra-abdominal testicle should be considered where an abdominal mass with calcification is found in an infant with undescended testis. Ultrasonography improves the diagnostic accuracy in infants because of the cystic nature of these masses in this age group.

Cryptorchidism↗

PubMed1994

Prognosis of neuroblastic tumours in children.

A retrospective analysis of 26 children with neuroblastic tumours treated at the University Hospital of the West Indies (UHWI) between 1970 and 1991 was undertaken to evaluate factors affecting prognosis. The peak incidence was between 48 months and 60 months of age, and 75% of the deaths occurred in children older than 3 years. The abdomen was the most common site of the tumours 79% of which were from the adrenal gland and carried a dismal outcome. Other sites were thoracic, pelvic and cervical. Extra-adrenal tumours have a good outcome even when the histology is unfavourable; 92% of the tumours were in Stages III or IV at the time of initial presentation. Stage IV disease accounted for all but one of the deaths. Of the 8 children with favourable histology (ganglioneuroma or well-differentiated ganglioneuroblastoma), only one (12.5%) died, wheras of the remaining 18 cases with unfavourable histology (neuroblastoma and undifferentiated ganglioneuroblastoma), eleven (61.1%) died. When managed by surgery alone or with adjuvant chemo- and/or radio-therapy, only 36.4% succumbed while all 4 children with chemotherapy only died. Ten children are alive without disease for more than three years post-therapy. A scoring system was designed which takes into account the factors influencing the outcome in neuroblastic tumours, namely, age, location, stage and histological types of the tumours and therapy. All the children with a score of 21 or less survived, whereas all those with scores of 22 or above succumbed. This underlines the multifactorial influences on the final outcome of neuroblastic tumours.

Abdominal Neoplasms↗

PubMed1994

Outcome of solid renal tumours in children at the University Hospital of the West Indies.

Of the twenty-nine children with solid renal tumours treated at the University Hospital of the West Indies (UHWI) between January, 1972 and December, 1991, there were twenty-eight cases of nephroblastoma and one of mesoblastic nephroma. Peak incidence was between the ages of two and four years. Twenty-five children had radical nephrectomy while one had bilateral partial nephrectomy. In thirteen cases, pre-operative chemotherapy +/- radiotherapy was used. Post-operative chemotherapy and radiotherapy were used in 24 and 13 cases, respectively. Stage of the tumour was the most decisive factor influencing the outcome. Whereas there was a 100% cure rate in Stages I and II, Stage III had only a 55.5% survival rate and none of the Stage IV survived. Bilateral (Stage V) tumours are curable if individual tumours are localised, as in one of the two cases. The benign mesoblastic nephroma, in a one-month-old infant, was cured by nephrectomy alone. While the present therapy of radical nephrectomy along with combination chemotherapy is satisfactory for early stages, more aggressive adjuvant therapy is needed for improving the results in Stages III and IV.

Child↗

PubMed1994

The Rapunzel syndrome. Report of a case and review of the literature.

The Rapunzel Syndrome, a rare manifestation of trichobezoar, occurs when bolus gastrointestinal obstruction is produced by an unusual trichobezoar with a long tail that extends to or beyond the ileocaecal valve. A five-year-old Jamaican girl presented with this abnormality and was found at laparotomy also to have an ileo-ileal intussusception. For the Rapunzel Syndrome, we recommend bezoar extraction at laparotomy via multiple enterotomies. In addition, psychiatric evaluation and therapy is essential due to the commonly associated finding of underlying emotional stress.

Bezoars↗

PubMed1993

Hydrops of the gallbladder.

Hydrops of the gallbladder is an uncommon condition of infants and children. There is acute distension of the gallbladder in the absence of calculi without evidence of inflammation in the early stages of the disease. A case of hydrops of the gallbladder in a 4-year-old male child is presented. The literature is reviewed and the diagnosis and treatment of the condition discussed.

Anti-Bacterial Agents↗

PubMed1992

Biliary surgery in patients with sickle-cell anaemia.

The results of biliary surgery are reported in 12 consecutive patients with homozygous sickle-cell (SS) disease treated over a two-year period at the University Hospital of the West Indies, Kingston, Jamaica. Recommendations for the surgical management of these patients are outlined.

Adolescent↗

PubMed1989

Visceral complications of electrical burn injury. A report of two cases and review of the literature.

Two patients with high voltage electrical injury involving the trunk are presented. Both injuries were complicated by visceral damage; and one patient died from sepsis secondary to bowel perforation. The rarity of this complication is examined in light of the pathophysiology of electrical injury; and its management is discussed with reference to previously published reports on this condition.

Burns, Electric↗

PubMedDate not supplied

The effect of heavy resistance exercise on the circadian rhythm of salivary testosterone in men.

Circadian rhythms of serum testosterone concentrations in men have been shown, in general, to be highest in the morning and lowest in the evening. Thus, the purpose of this investigation was to determine the effects of acute resistance exercise upon the waking circadian rhythm of salivary testosterone over 2 days (with or without resistance exercise). The subjects included ten resistance-trained men (with at least 1 year of lifting experience) with the following characteristics [mean (SD)]: age 21.6 (1.1) years; height 177.8 (9.5) cm; body mass 80.5 (11.5) kg; percent body fat 7.9 (1.7)%. A matched, randomized, crossover study design was used such that each subject was tested under both the resistance exercise and control (no exercise) conditions. The resistance exercise protocol consisted of ten exercises performed for three sets of ten repetitions maximum with 2 min of rest between sets. Saliva sample 1 was collected at 0615 hours and resistance exercise began immediately afterwards at approximately 0620 hours, and sample 2 was collected at 0700 hours, which corresponded approximately to a mid-exercise (or control) time point. Saliva samples were then obtained every hour on the hour from 0800 hours until 2200 hours. No significant differences were observed between the exercise and resting conditions for salivary testosterone, with the exception of a significant decrease at 0700 hours during the resistance exercise protocol. The results of this investigation indicate that resistance exercise does not affect the circadian pattern of salivary testosterone secretion over a 16-h waking period in resistance-trained men.

Adult↗

PubMedDate not supplied

Endurance training effects on the contractile activation characteristics of single muscle fibres from the rat diaphragm.

1. Considerable debate exists as to whether the properties of diaphragm muscles can be modified by training. As the diaphragm is chronically activated during normal respiration, it is of interest to determine whether this muscle is resistant to further modification by exercise. The aim of this study was to investigate the contractile activation characteristics of single skinned muscle fibres from the diaphragm of both CONTROL and TRAINED rats. 2. Male rats were subjected to a 20 week high-intensity endurance exercise training programme that consisted of running on a motorized treadmill, 5 days/week, 90-120 min/day, 27-30 m/min, up a 20 degrees incline. At the conclusion of training, rats were killed with an overdose of ether and costal regions of the diaphragm were removed and stored in a glycerol-based skinning solution at -20 degrees C. 3. Single skinned (membrane-permeabilized) diaphragm muscle fibres were attached to a sensitive force transducer and activated in Ca(2+)- and Sr(2+)-buffered solutions in order to determine relative force-pCa and force-pSr characteristics. Fibres were allocated into discrete groups (population I, population II, intermediate, mixed) on the basis of their physiological (contractile) properties. 4. Population I (slow-twitch) fibres from the diaphragm of TRAINED rats exhibited a reduced sensitivity to Ca2+ (indicating a rightward shift of the force-pCa relationship) compared to those diaphragm fibres from CONTROL animals. An increased number of population II (fast-twitch) fibres were sampled from TRAINED rats, however, training did not affect the activation properties of these fibres.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗