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Biomedical subjects

J Butler

Publications and source records attributed to J Butler.

At least 37 records · Page 2Linked to original sources
PubMed1991

Quantitative determination of trucking industry workers' exposures to diesel exhaust particles.

As part of a case-control mortality study of trucking industry workers, exposures to diesel aerosol were measured among the four major presumably exposed job groups (road drivers, local drivers, dock workers, and mechanics) in the industry. Eight industrial hygiene surveys were conducted during both warm and cold weather at eight U.S. terminals and truck repair shops. A single-stage personal impactor was used to sample submicrometer-sized diesel particles on quartz fiber filters. Laboratory and field studies demonstrated that the elemental carbon content of the particles is a useful and practical marker of exposure to vehicular diesel exhaust. A thermal-optical analysis technique was used to determine the concentration of elemental carbon in the filter samples. Overall geometric mean exposures to submicrometer-sized elemental carbon ranged from 3.8 micrograms/m3 in road (long distance) drivers (N = 72) to 13.8 micrograms/m3 in dock workers (N = 75). Geometric mean background area concentrations, measured in the same cities where workers were sampled, were 2.5 micrograms/m3 on major highways (N = 21) and 1.1 micrograms/m3 in residential areas (N = 23). A factorial analysis of variance indicated that exposures in two job groups, dock workers (particularly those exposed primarily via diesel forklift trucks, introduced relatively recently) and mechanics (working in poorly ventilated shops during cold weather), were significantly higher than background concentrations and were significantly higher than the exposures in the local and road drivers. The exposures of the truck drivers could not be distinguished from background highway concentrations but were significantly higher than background concentrations in residential areas.

Air Pollutants, Occupational↗
PubMed1991

Intra-ocular pressure changes using the laryngeal mask airway and tracheal tube.

Intra-ocular pressure was measured before and throughout airway establishment with either the laryngeal mask airway or tracheal tube. Similar measurements were made on removal of either airway and the amount of coughing noted in the first minute after removal. There was a significantly smaller increase in intra-ocular pressure (p less than 0.001) using the laryngeal mask airway, both on placement and removal, than with the tracheal tube. Postoperative coughing was significantly reduced using the laryngeal mask airway (p less than 0.001). There was a significantly greater rise in heart rate using the tracheal tube (p less than 0.01) probably related to an increased cardiovascular response. The laryngeal mask airway is recommended as an alternative to tracheal intubation in routine and emergency intra-ocular surgery.

Aged↗
PubMed1991

Association between autoimmune thyroid disease and familial Alzheimer's disease.

OBJECTIVE: To determine the prevalence of autoimmune thyroid disease in Familial Alzheimer's Disease kindreds and to ascertain whether there is any evidence for genetic linkage between the two conditions. DESIGN: Retrospective study of Familial Alzheimer's Disease kindreds. PATIENTS: Seventy affected and unaffected family members from 12 kindreds. MEASUREMENTS: Anti-thyroglobulin and anti-microsomal autoantibody status was determined using an enzyme-linked immunosorbent assay. Thyrotrophin levels were determined by an immunoradiometric assay. RESULTS: Of the family members, 41.4% had evidence of autoimmune thyroid disease, with significant co-segregation between the presence of thyroid autoantibodies and the development of Alzheimer's disease (P less than 0.01). CONCLUSIONS: This study demonstrates a very high prevalence of autoimmune thyroid disease in Familial Alzheimer's Disease kindreds and suggests that a genetic factor contributing towards the development of autoimmune thyroid disease may be located on chromosome 21 within close proximity to the Familial Alzheimer's Disease gene.

Adult↗
PubMed1991

Amenorrhoea in women with non-alcoholic chronic liver disease.

Amenorrhoea is common in women with non-alcoholic chronic liver disease, but little is known about its causes or consequences. We investigated 12 young women with non-alcoholic chronic liver disease and amenorrhoea and compared them with 11 healthy age matched controls studied in the follicular phase of the menstrual cycle. None of the patients had raised serum concentrations of follicle stimulating hormone suggesting primary gonadal failure, but the variance in serum concentrations of testosterone, oestradiol, prolactin, and luteinising hormone were significantly greater in chronic liver disease patients than control subjects (p less than 0.01). Seven of the 12 chronic liver disease patients had low serum luteinising hormone concentrations, and compared with controls these patients also had significantly reduced median values of oestradiol (64 pmol/l), testosterone (1.1 nmol/l), and follicle stimulating hormone, and were significantly underweight as assessed by skinfold thickness measurements (all comparisons p less than 0.025). In the group with chronic liver disease skinfold thickness was significantly correlated with serum luteinising hormone (p less than 0.02). The five patients with normal serum luteinising hormone had higher median values of both oestradiol (237 pmol/l) and testosterone (3.0 nmol/l) than the control subjects (oestradiol: 113 pmol/l, testosterone: 1.9 nmol/l) but were not more obese or hirsute. Amenorrhoea was unrelated to the duration or severity of liver disease. The metacarpal cortical bone area (an index of bone density) was inversely related to the duration of amenorrhoea (p less than 0.02). We conclude that amenorrhoea in women with non-alcoholic chronic liver disease arises from hypothalamic-pituitary dysfunction and can occur at any stage. The hormonal findings in amenorrhoeic chronic live disease patients are not uniform. In some, hypogonadotrophic hypogonadism is related to undernutrition whereas others have normal to high values of luteinising hormone and sex steroids. Prolonged oestrogen deficiency can be a risk factor for osteoporosis in women with chronic liver disease.

Adult↗
PubMed1991

Life-threatening hypercalcaemia in association with Addisonian crisis.

A 35 year old woman was admitted with acute radial artery occlusion necessitating two operations and thrombolytic therapy. Subsequently a diagnosis of primary hypothyroidism was made and she was commenced on thyroxine replacement therapy. Her condition, however, continued to deteriorate with the development of an Addisonian crisis heralded by, and complicated by, severe, life-threatening hypercalcaemia. This case highlights the importance of considering Addison's disease in any patient whose condition deteriorates after the introduction of thyroxine replacement, and illustrates the often forgotten association of hypercalcaemia and hypoadrenalism.

Addison Disease↗
PubMed1991

Bilateral diaphragm paralysis after cardiac surgery with topical hypothermia.

Bilateral diaphragm paralysis is a rare but important complication of open heart surgery. Two cases were found among 360 prospectively studied patients undergoing open heart surgery during one year. Both patients had insulin dependent diabetes with peripheral neuropathy and this may have contributed to their diaphragm paralysis. The patients were studied postoperatively for one year with measurements of lung function, nocturnal oximetry, diaphragmatic function, and phrenic nerve conduction. Treatment with intermittent positive airway pressure ventilation by nasal mask was effective in both patients. After nine months one patient had recovered completely with normal phrenic nerve conduction and diaphragmatic function; the other continues most of his normal daytime activities, but still requires nasal positive airway pressure ventilation for six hours at night.

Cardiac Surgical Procedures↗
PubMed1991

Influence of lung volume and left atrial pressure on reverse pulmonary venous blood flow.

Infarction of the lung is uncommon even when both the pulmonary and the bronchial blood supplies are interrupted. We studied the possibility that a tidal reverse pulmonary venous flow is driven by the alternating distension and compression of alveolar and extra-alveolar vessels with the lung volume changes of breathing and also that a pulsatile reverse flow is caused by left atrial pressure transients. We infused SF6, a relatively insoluble inert gas, into the left atrium of anesthetized goats in which we had interrupted the left pulmonary artery and the bronchial circulation. SF6 was measured in the left lung exhalate as a reflection of the reverse pulmonary venous flow. No SF6 was exhaled when the pulmonary veins were occluded. SF6 was exhaled in increasing amounts as left atrial pressure, tidal volume, and ventilatory rates rose during mechanical ventilation. SF6 was not excreted when we increased left atrial pressure transients by causing mitral insufficiency in the absence of lung volume changes (continuous flow ventilation). Markers injected into the left atrial blood reached the alveolar capillaries. We conclude that reverse pulmonary venous flow is driven by tidal ventilation but not by left atrial pressure transients. It reaches the alveoli and could nourish the alveolar tissues when there is no inflow of arterial blood.

Animals↗
PubMed1991

Endocrine function, psychiatric and clinical consequences in patients with macroprolactinomas after long-term treatment with the new non-ergot dopamine agonist CV205-502.

Although bromocriptine is the mainstay of treatment of macroprolactinomas, its therapeutic usefulness may be limited by poor tolerance, lack of consistent reduction in serum prolactin levels and tumour size, and the necessity for multiple dosing. Consequently new dopamine agonists have been developed, including the long acting non-ergot agonist CV205-502 which has been shown to date to be consistently effective in reducing serum PRL levels and causing tumour shrinkage. Twelve patients were treated for periods of up to 24 months with CV205-502 in doses ranging from 0.075 mg to 1.65 mg once daily. Clinical and psychiatric assessments, biochemical parameters, tumour size determination, and anterior pituitary function tests were performed regularly. Tumour shrinkage was noted in all patients, and varied from 11 per cent reduction to complete disappearance of tumour. Prolactin levels became normal in seven patients and were reduced by more than 90 per cent in the remaining five. Normal menstruation resumed in six of the eight women, one of whom conceived after one year of therapy; libido returned in all patients. Psychiatric complications occurred in three patients necessitating withdrawal of therapy in one. Significant weight loss was noted in 11 of 12 patients. Triglyceride concentrations fell from 1.5 +/- 0.1 to 1.0 +/- 0.1 mmol/l at 12 months (p = 0.006), and cholesterol fell from 6.3 +/- 0.4 to 5.3 +/- 0.3 mmol/l (p = 0.04). The mean TSH response 20 min following TRH injection fell from 14.3 +/- 2.9 to 8.7 +/- 1.3 mU/l at 2 months (p = 0.027). There was a significant increase in the peak growth hormone response to the insulin stress test from basal median (25th-75th centiles) values of 15 (4.4-25.5) mU/l to 24.5 (9-37) mU/l at 2 months (p less than 0.01) and 31 (19.3-63.5) at 12 months (p less than 0.005). CV205-502 is highly effective in the medical management of patients with macroprolactinomas, reducing prolactin levels and tumour size and restoring normal anterior pituitary function. It is, however, associated with the important side effects of weight loss and psychiatric complications which should be drawn to the attention of clinicians.

Adult↗
PubMed1991

Hyperbaric oxygen therapy: treatment for spinal cord decompression sickness.

Spinal cord injury (SCI) may result from decompression sickness associated with sport and commercial diving. Decompression sickness is caused by the formation of gas bubbles in the vessels and tissues secondary to a reduction in ambient pressure. A complete or incomplete spinal cord injury may result from decompression sickness. Recompression and hyperbaric oxygen therapy is the primary treatment. The use of hyperbaric oxygen therapy (HBO) as a treatment for these injuries can greatly influence the patient's outcome. Early intervention in a recompression chamber may result in complete recovery. If treatment is delayed however, the prognosis for recovery is poor.

Decompression Sickness↗
PubMed1991

Catecholamine concentrations in the hepatic portal system: effect of surgical stress upon portal levels.

The biological effects of a hormone are dependent on the concentration delivered to the target tissue. This is generally best reflected in the arterial concentration. However, the liver is unique in that it receives substantial additional blood flow from the portal venous system. This may be important in the case of the catecholamines, where extraction or spillover from the splanchnic circulation may occur. In this study we examined portal venous catecholamine concentrations in anesthetized, laparotomized rabbits. We compared the values with simultaneously sampled arterial levels to evaluate the effects of the splanchnic tissues upon a wide range of catecholamine concentrations delivered to the liver during a state of stress. Spillover of norepinephrine and extraction of epinephrine were observed in all rabbits. Mean (+/- SEM) arterial norepinephrine concentrations were elevated, 716 +/- 167 pg/ml (n = 11); mean portal concentrations were 178 +/- 37% higher (p less than 0.01), at 1,425 +/- 301 pg/ml, representing net spillover from splanchnic tissues. In addition, significant extraction of epinephrine was observed; arterial concentrations were 2,144 +/- 580 pg/ml (n = 11). Portal levels were 1,205 +/- 382 pg/ml, 38 +/- 7.45% lower than corresponding arterial concentrations (p less than 0.02). Furthermore, there was a concentration-dependent effect upon norepinephrine spillover; the highest arterial norepinephrine concentrations were associated with the lowest splanchnic spillover. This resulted in a negative correlation between the arterial norepinephrine levels and the percent increase from spillover into the portal vein (r = -0.81, p less than 0.003). We conclude that portal venous catecholamine concentrations are significantly different from arterial levels in anesthetized, laparotomized rabbits over a wide range of concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Diagnostic delay and outcome in surgery for type A aortic dissection.

Twenty-two patients with acute type A aortic dissection presented to this hospital over a three-year period. The initial diagnosis was incorrect in 12 (54.5 per cent) and in 11 of these the error occurred in peripheral hospitals before referral. This diagnostic mistake lead to a delay in surgical treatment of 2-9 days (median 5 days). Three deaths occurred without surgery, and two of these could have been considered for repair if the correct diagnosis had been made earlier. In the surgically treated group, a 30-day survival of 16 out of 19 (84.2 per cent) was achieved and the three deaths were all related to late referral. Two died because of bowel infarction and one because of respiratory failure. An increased general awareness of acute aortic dissection is necessary as early diagnosis, before the onset of irreversible ischaemic events, allows a high surgical success rate.

Acute Disease↗
PubMed1990

Comparison of the structural and cytotoxic activity of novel 2,5-bis(carboethoxyamino)-3,6-diaziridinyl-1,4-benzoquinone analogues.

Eight analogues of 2,5-bis(carboethoxyamino)-3,6-diaziridinyl-1,4-benzoquinone have been synthesized and tested for cytotoxicity against four different leukemic and lymphomic cell lines. For K562 and BSM cells, the toxicity could be correlated with the ease of reduction of the compounds as determined by the one-electron reduction potentials and the electron spin resonance detection of the reduced compounds produced by the cells. The cell toxicity could also be correlated with the efficiency of the compounds to form cross-links in DNA. However, no such correlations could be observed for the L1210 and Raji cells, although the activity of the NADPH dependent reducing enzymes in these cells was similar to that in the others. It is believed that for the L1210 and Raji cells, the influx/efflux of the different compounds may be more important to the cytotoxicity than their reduction or alkylation.

Animals↗
PubMed1990

The drainage routes of the bronchial blood flow in anesthetized dogs.

It is generally accepted that the bronchial blood flow from extrapulmonary airways drains to the systemic veins through the bronchial veins, while that from the intrapulmonary airways drains into the pulmonary vasculature and eventually the left heart. This concept has not been confirmed by physiologic studies in live animals. We measured the routes taken by radionuclide-labeled Diethylenetriamine pentaacetate (DTPA) deposited in the extrapulmonary and the intrapulmonary airways in dogs. In living, anesthetized open chest animals, the pulmonary circulation of the left lower lobe was isolated and perfused with autologous heparinized blood. 99mTc DTPA was deposited on the mucosa of the extrapulmonary left mainstem bronchus just beyond the main carina (extrapulmonary deposition) and 111In DTPA on that of an intrapulmonary left lower lobe segmental bronchus (intrapulmonary deposition). Sequential blood samples from the right heart and from the isolated left lower lobe pulmonary circuit were counted for radioactivity, corrected for the volume in which they were distributed and for the bronchial blood that flowed into the isolated left lower lobe circuit, and expressed as the ratio of systemic to pulmonary drainage from each deposition site. The extrapulmonary tracer drained mostly to the systemic veins (84% of total) but also into the pulmonary circulation (16% of total). The intrapulmonary tracer drained mostly into the pulmonary circulation (70% of total) but also into the right heart (30% of total). Since tracers from both deposition sites drained to both circulations, the bronchial vasculature is continuous between the systemic (right heart) and the pulmonary circulation. Thus, it may provide a pathway for blood flow between the right and left heart.

Anesthesia↗
PubMed1990

The effect of bronchial venous pressure on pulmonary edema in the dog.

We examined the effect of elevating systemic venous pressure on the rate of edema formation in the left lower lobes (LLL) of anesthetized, open-chested dogs. The pulmonary circulation of the LLL was isolated using cannulae in the artery and vein which were attached to blood-filled reservoirs. The LLL was distended to an alveolar pressure of 25 cm H2O with 5% CO2 and air, and suspended from a strain gauge which allowed continuous weight recording. The pulmonary vascular pressures were raised so all of the LLL was in zone III. The rate of weight change occurring over the last 4 minutes of a 6 minute period of this pulmonary vascular pressure rise was taken to represent the control transvascular fluid flux. The rate of weight gain of the LLL was then determined with the same pulmonary vascular pressure elevation only when downstream bronchial venous pressure alone, downstream lymphatic pressure alone, or when both downstream lymphatic and bronchial venous pressures were elevated. The transvascular fluid flux was increased when downstream bronchial venous pressure was elevated. When only downstream lymphatic pressure was elevated there was no augmentation of transvascular fluid flux. These findings suggest that when a lung is already subjected to raised pulmonary vascular pressure sufficient to cause edema, acute elevation of bronchial systemic venous pressure augments the net rate of outward fluid flux, while downstream lymphatic pressure elevation does not.

Animals↗
PubMed1990

Interaction of copper(I) with nucleic acids.

Poly(dG-dC) and poly(I) form particularly stable complexes with Cu(I): thus characteristic UV absorbance changes enabled demonstration of Cu(I) transfer from poly(dA-dT) to poly(dG-dC), or from DNA to poly(I). Using pulse radiolysis to generate Cu(I), a rate constant of approximately 4 x 10(7) dm3 mol-1 s-1 (per base unit) was estimated for association of Cu(I) to native DNA, and slightly higher values were found for poly(dA-dT), poly(C), poly(dG-dC) and poly(G). For native DNA and for the models poly(dA-dT) and poly(dG-dC) the addition of Cu(I) was followed by secondary absorbance changes in the time scale of 10 ms, probably due to internal Cu(I) transfer; such secondary reactions were not detectable in heat-denatured DNA or in the homopolymers of A, C, G, and I. Extraction of Cu(I) from the DNA by EDTA is slow, 0.019 s-1, and independent of EDTA concentration, indicating that dissociation of the DNA-Cu(I) complex is the rate-determining step. A tentative value can hence be given for the DNA-Cu(I) stability constant: K = k (forward)/k (reverse) approximately 2 x 10(9) dm3 mol-1. Addition of H2O2 to solutions of gamma-radiolytically generated DNA-Cu(I), at Cu(I)/base less than 0.01, resulted in DNA degradation, comparable in yield to .OH-induced degradation. In the case of poly(dA-dT) and poly(dG-dC) the reaction of H2O2 with the corresponding Cu(I) complexes produced even more damage than the reaction of .OH. The formation of DNA-Cu(I), and the deleterious reaction with H2O2, were hardly affected by RNase or BSA, when added at equal (w/v) concentration. Dismutation of O2.- by (Cu,Zn)-SOD was partly inhibited by DNA and even more by poly(I) at pH 4.4, but not at pH 7, probably by competitive complexation of Cu(I), occurring in the catalytic cycle of SOD.

Copper↗