Insulin regulation of pyruvate kinase activity in isolated adipocytes. Crucial role of glucose and the hexosamine biosynthesis pathway in the expression of insulin action

We recently identified glutamine:fructose-6-phosphate amidotransferase (GFAT) as an insulin-regulated enzyme in adipocytes. Moreover, we found that loss of GFAT activity is not due to a direct action of insulin but rather is mediated by enhanced glucose uptake and the subsequent routing of glucose through the hexosamine biosynthesis pathway. To assess whether other cytosolic enzymes are controlled through formation of hexosamine products, we treated adipocytes for 5 h with physiological concentrations of insulin (ED50 = 0.33 ng/ml), glucose (ED50 = 4.5 mM), and glutamine (ED50 = 4.4 mM) and then measured pyruvate kinase (PK) activity. Combined treatment resulted in a progressive (t 1/2 of 2.5 h) and marked (3-fold) increase in PK activity, whereas omission of one or more of these components failed to alter enzyme activity. Several lines of additional evidence implicated the hexosamine biosynthesis pathway in PK regulation; therefore, it appears that the M2 isoform of pyruvate kinase represents another enzyme regulated by insulin through stimulation of glucose uptake and formation of hexosamine products. Related studies revealed that enhancement of PK activity is dependent upon ongoing mRNA synthesis and de novo protein synthesis and is mediated by an increase in enzyme content. Considered together, these findings provide new insights into the cascade of metabolic events triggered by insulin and implicated a novel metabolic pathway in the pretranslational control of enzyme function.

A comparative analysis of two models of colitis in rats

Two models of colitis produced in rats that have received significant attention over the past few years are the acetic acid and trinitrobenzene sulfonic acid (TNBS) models. The objective of this study was to quantify and compare the temporal relationship among mucosal permeability, epithelial injury, and inflammation induced by acetic acid, ethanol (vehicle), ethanol plus TNBS (unbuffered, pH 1.0), and ethanol plus TNBS (pH 7.4). Data obtained show that the inflammation induced by these four irritants results from caustic injury to the colonic epithelium and interstitium as measured by the rapid and dramatic increases in mucosal permeability and tissue water content as well as by histological analysis. The injurious nature of TNBS was confirmed in a separate series of studies showing that buffered TNBS (pH 7.4), in the absence of ethanol, is toxic to cultured rat intestinal epithelial cell monolayers. Only after 1-2 days of the initial insult, were signs of classical inflammation observed, including increases in colonic myeloperoxidase activity (neutrophil infiltration) and colon weight as well as hyperemia and mucosal ulcerations. Although ethanol plus TNBS (pH 1.0 or 7.4) tended to produce higher mucosal permeabilities (epithelial cell injury) at 1-2 weeks after the enemas than acetic acid or ethanol groups, only the ethanol plus TNBS (pH 7.4) permeabilities were found to be significantly enhanced. In addition, all four groups showed significant elevations in colonic myeloperoxidase activity and colon weight at 1-2 weeks after enema. It is suggested that these models of colitis are useful to study events that occur at the time of inflammation and repair. However, these models may have significant limitations in understanding events that initiate inflammation of the intestine in human inflammatory bowel disease.

Detection of inspiratory resistive loads by heart-lung transplant recipients

Human heart-lung transplantation recipients (HL) are models for the effects of selective lower respiratory tract denervation. We used a series resistor to examine thresholds of inspiratory flow resistance perception among 16 HL in comparison with 15 normal control subjects (C) and 12 heart transplant recipients (H). HL and C were closely age matched. H subjects were older and had mildly reduced lung volumes compared with the other groups. The perception threshold was defined as the added resistance (delta R) detected by subjects at 50% of random, blinded presentations. These delta R were subsequently expressed as a fraction of the airway resistance of the subject and baseline resistance of the apparatus (delta R/Raw + Rapparatus), otherwise known as the Weber fraction. The mean +/- SEM Weber fractions were nearly identical for HL and C (0.32 +/- 0.05 versus 0.34 +/- 0.05, respectively). The Weber fraction of H (0.74 +/- 0.17) was significantly greater than those of both other groups (p less than 0.05 by Kruskal-Wallis test). We conclude that lower respiratory tract afferents do not play a significant role in the perception of inspiratory resistive loads. The finding of an abnormally high Weber fraction in the heart transplant population remains unexplained but may be a function of age or restrictive pulmonary defects.

Cardiac function after domino-donor heart transplantation

A major limitation in cardiac transplantation is donor availability. A possible way to increase the supply of donor hearts is to use explanted hearts from patients undergoing heart-lung transplantation for primary lung disease. One potential advantage of this approach, termed domino-donor transplantation, is the existence of a donor right ventricle already adapted to pulmonary hypertension, which would therefore theoretically decrease the likelihood of acute donor right heart failure in recipients with preexisting elevation of pulmonary vascular resistance. Potential disadvantages include graft failure secondary to chronic effects of pulmonary hypertension on the right ventricle, arrhythmia and infections. Seven domino-donor transplants were performed at Stanford University Hospital; graft and patient survival to date are 100% at a mean follow-up of 20 months (range 1 to 26). Infection and rejection rates have been comparable to those of the current Stanford experience for conventional orthotopic transplantation. Right ventricular function and size have either improved or remained unchanged in all patients after transplantation. Transient early postoperative donor right ventricular dilation, a characteristic adaptive response seen in nondomino transplants, occurred in 4 patients with pulmonary hypertension before surgery. These data indicate that, with adequate assessment before surgery, domino-donor cardiac transplantation is an appropriate means of augmenting the donor pool.

Normal growth with renal insufficiency owing to posterior urethral valves: value of long-term diversion. A twenty-year follow-up

Twenty-five patients with posterior urethral valves have been monitored for 10-29 years (mean 18 years). Eight underwent diversion because of impaired renal function (creatinine greater than 0.8 mg/dl) accompanied by unimproved upper tract form and function after valve ablation. In the nondiverted group, 6 patients (35%) progressed to renal failure; in the diverted group 5 patients (63%) did so (p = 0.30). Of 13 patients whose lowest serum creatinine in the first year after valve ablation was greater than 0.8 mg/dl, 9 (69%) went on to renal failure (p = 0.02); in the remaining 12 patients, only 2 (17%) did so (p = 0.008). The mean age for renal failure was 13 years for both groups. The Tanner scale rating (mean percent height) for all patients at 10 years was 61% for the diverted group and 35% for those without diversion (p = 0.004). When the patients treated after the age of 1 year (n = 7) were excluded from the calculation, the rating remained different (54% diversion, 26% no diversion; p = 0.012). We conclude that the boy born with urethral valves and serious upper tract damage is at risk for renal failure, especially during the teen years. An undefined relationship appears to exist between urinary obstruction and growth. In our study, the boys who underwent diversion continued to grow along a normal Tanner height curve.

No evidence for social class inequalities in intervention for coronary heart disease in Otago 1987-9

OBJECTS

to investigate whether social class differences in access to cardiac surgical interventions (angioplasties and coronary artery bypass grafting) could explain social class inequalities in mortality from coronary heart disease.

METHODS

rates of therapeutic interventions to treat coronary heart disease were calculated for male patients aged less than 65 years admitted for the first time to Dunedin Hospital with a principal diagnosis of ischaemic heart disease (ICD codes 410-414) during the three year period from 1 January 1987 to 31 December 1989. Patients were categorised into different socioeconomic groups using the Elley-Irving social class scale.

RESULTS

no statistically significant trend across social class was observed in the cumulative incidence of cardiac surgical interventions (angioplasties, coronary artery bypass grafts). Similarly there was no statistically significant trend across social class in the incidence rates of cardiac surgical interventions, even after adjustment for age.

CONCLUSIONS

social class inequalities in access to cardiac surgical intervention do not appear to explain the observed inequalities in mortality from coronary heart disease.

New insights into the metabolic regulation of insulin action and insulin resistance: role of glucose and amino acids

In primary cultured adipocytes, metabolic substrates such as glucose and amino acids have profound effects on modulating insulin's stimulatory actions on glucose uptake and protein synthesis. Insights into how substrates modulate insulin action were recently obtained when we discovered that the routing of incoming glucose through the hexosamine biosynthesis pathway leads to a refractory state over a period of several hours in which the ability of insulin to stimulate glucose uptake is severely impaired--a state known as insulin resistance. Glutamine:fructose-6-phosphate amidotransferase was found to play a central role in the development of insulin resistance as this enzyme catalyzes the first and rate-limiting step in the formation of hexosamine products. Collectively, these results are consistent with the idea that the hexosamine biosynthesis pathway serves as a glucose sensor coupled to a negative feedback system that can limit the extent of glucose uptake in response to hyperglycemic and hyperinsulinemic conditions.

Mania and seasonality in the southern hemisphere

Admissions for mania over a 9-year period in New Zealand were analysed, including data from four separate regions spanning nine degrees in latitude. A spring/summer peak of admissions for mania was found. The four regions showed marked, unexpected variability in seasonality. Regression analyses were performed to test the association of admissions for mania, in the month of admission and the previous month, with mean daily temperature, day length, hours of bright sunshine and mean relative humidity plus the rate of change of each of these variables.

Vitamin K status of lactating mothers, human milk, and breast-feeding infants

Hemorrhagic disease of the newborn is a disease of breast-feeding newborns. There is little information on longitudinal breast milk concentrations of phylloquinone (vitamin K1) or the effects of maternal phylloquinone supplements on breast milk. In study part 1, 11 lactating mothers, who received 20 mg of phylloquinone orally, had rises in plasma (less than 1 to 64.2 +/- 31.5 ng/mL by 6 hours) and breast milk concentrations (from 1.11 +/- 0.82 to 130 +/- 188 ng/mL by 12 hours). In part 2, 23 lactating mothers and their infants were observed longitudinally along with a formula-fed control group of infants (n = 11). Mean breast milk concentrations of phylloquinone at 1, 6, 12, and 26 weeks were 0.64 +/- 0.43, 0.86 +/- 0.52, 1.14 +/- 0.72, and 0.87 +/- 0.50 ng/mL, respectively, in the infants fed human milk. Maternal phylloquinone intakes (72-hour dietary recalls) exceeded the recommended daily allowance of 1 microgram/kg per day. Infant phylloquinone intakes did not achieve the recommended daily allowance of 1 microgram/kg per day in any infant. Plasma phylloquinone concentrations in the infants fed human milk remained extremely low (mean less than 0.25 ng/mL) throughout the first 6 months of life compared with the formula-fed infants (4.39 to 5.99 ng/mL). In this small sample, no infant demonstrated overt vitamin K deficiency. Despite very low plasma phylloquinone concentrations, vitamin K supplements (other than in the immediate newborn period) cannot be recommended for exclusively breast-fed infants based on these data.

Prostate irradiation does not affect the serum prostatic acid phosphatase level

Twenty-nine consecutive patients with localized prostatic carcinoma were studied prospectively to assess the effect of radical pelvic irradiation on the serum prostatic acid phosphatase level (SPAPL). The doses of radiation given ranged from 64.00 to 66.00 Gy. SPAPLs were taken before, during and shortly after their treatment. No significant individual variations in SPAPLs were found. When patients with prostatic carcinoma show rises in serum prostatic acid phosphatase during or after pelvic irradiation, these are unlikely to be due to their treatment and occult pelvic nodal or bony disease should be considered.

The influence of growth hormone and thyroxine on iodothyronine deiodinase activity in the liver, kidney and brown adipose tissue in hypophysectomized rats

The effects of GH and T4 substitution on peripheral iodothyronine deiodinase activity in the liver, kidney and brown adipose tissue of hypophysectomized rats were investigated. Animals were treated with GH (140 micrograms hGH/day), T4 (3 micrograms/day), GH plus T4 (same doses), or saline. Rats were killed 0, 4, 7 or 11 days after treatment was started. Non-hypophysectomized, age-matched rats were killed after 0 and 11 days and served as controls. GH plus T4 restored body weight gain to normal, whereas GH alone and T4 alone did not. Tissue deiodinase activity and T3 concentrations were severely depressed in the hypophysectomized rats compared with non-hypophysectomized controls (to less than 10%). GH substitution in hypophysectomized rats led to a slight but significant elevation in tissue iodothyronine deiodinase activity in the liver and kidney, without concomitant increases in T3. Deiodinase activity in brown adipose tissue did not differ from that in saline-treated controls. T4 administration normalized deiodinase activity and tissue T3 content in all the evaluated tissues. GH plus T4 resulted in a lesser increase in deiodinase activity than T4 alone in the liver and kidney (p less than 0.01 at day 11), whereas no significant difference was observed in brown adipose tissue. In conclusion, GH stimulates iodothyronine deiodinase activity of the liver and kidney in hypophysectomized rats. Moreover, when GH is administered together with T4, the T4-stimulated enzyme activity in the liver and kidney is downregulated, suggesting that GH attenuates (or modulates) the T4 effect on this specific enzyme activity.

Coordinated regulation of glutamine:fructose-6-phosphate amidotransferase activity by insulin, glucose, and glutamine. Role of hexosamine biosynthesis in enzyme regulation

We reported previously that glutamine:F-6-P amidotransferase (GFAT) plays an integral role in the development of insulin resistance by directing the flow of incoming glucose into the hexosamine biosynthesis pathway. To determine whether the enzymatic activity of GFAT is altered during desensitization of the glucose transport system, we treated isolated rat adipocytes with various combinations of insulin, glucose, and glutamine. Treatment with insulin or glucose alone (or in combination) failed to reduce cytosolic GFAT activity after 4 h, whereas combined treatment with all three components elicited a progressive loss of GFAT activity that was rapid (t1/2 of 2 h) and extensive (70% loss). A pronounced loss of GFAT activity was also seen in cells exposed to glucosamine, an agent known to directly enter the hexosamine pathway (55% loss at 4 h, ED50 of 360 microM). Moreover, a close correlation was observed between the induction of desensitization and the loss of GFAT activity as a function of glucose, insulin, glutamine, and glucosamine concentrations. When total intracellular hexosamine products were measured, we found that hexosamine formation was unaltered by insulin or glucose (or a combination) but was elevated by greater than 4-fold in the presence of insulin, glucose, and glutamine (t1/2 of 22 min), a condition known to cause both desensitization and loss of GFAT activity. Additional studies indicated that the loss of GFAT activity under desensitizing conditions is not due to allosteric regulation since removal of potential allosteric factors from the cytosol of desensitized cells by G-25 column chromatography failed to restore enzyme activity. Overall, these studies indicate that 1) GFAT is an insulin-regulated enzyme; however, control of enzyme activity is not due to a direct action of insulin, but rather is mediated by insulin-induced enhancement of glucose uptake; 2) the routing of incoming glucose through the hexosamine pathway and the formation of hexosamine products appears to regulate GFAT activity; and 3) the progressive loss of GFAT activity over several hours is probably not due to allosteric regulation.

Complete inhibition of glucose-induced desensitization of the glucose transport system by inhibitors of mRNA synthesis. Evidence for rapid turnover of glutamine:fructose-6-phosphate amidotransferase

Glutamine:fructose-6-phosphate amidotransferase (GFAT) plays a key role in desensitizing the insulin-responsive glucose transport system (GTS), and recent studies have revealed that loss of GFAT activity accompanies desensitization. To gain insights into the mechanisms underlying loss of enzyme activity, we have used primary cultured adipocytes and two well established inhibitors of mRNA synthesis to estimate GFAT turnover. Both actinomycin D and 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) caused a rapid and extensive loss in GFAT activity (greater than 70% loss, t1/2 of 45 min) indicating that GFAT has a relatively short half-life. Since induction of insulin resistance requires GFAT, we next examined the ability of mRNA inhibitors to block glucose-induced desensitization. When adipocytes were cultured for 18 h with 20 mM glucose, amino acids, and 25 ng/ml insulin, maximal insulin responsiveness of the GTS was reduced by greater than 70%. Both actinomycin D and DRB rapidly and completely prevented desensitization in a dose-dependent manner (ED50 of 16 nM and 15 microM, respectively). These findings are the predicted functional consequence of diminished GFAT activity. Evidence that actinomycin D acts selectively on GFAT without influencing other steps within the desensitization pathway was obtained using glucosamine, an agent that enters the hexosamine biosynthesis pathway at a point distal to the action of GFAT. Actinomycin D inhibited glucose-induced desensitization but failed to block glucosamine-induced desensitization. From these studies we conclude that 1) glucose-induced desensitization of the GTS can be completely prevented by actinomycin D and DRB, two potent and diverse inhibitors of mRNA synthesis; 2) the functional integrity of the desensitization pathway is maintained by a short-lived protein; and 3) the identity of this short-lived protein is most likely GFAT, the first and rate-limiting enzyme of the hexosamine biosynthesis pathway.

Social class inequalities in the decline of coronary heart disease among New Zealand men, 1975-1977 to 1985-1987

Coronary heart disease (CHD) is regarded as a disease of developed 'western' societies. Within developed societies, however, CHD is typically a disease of the less affluent socioeconomic classes. This has not always been the case. Forty years ago. CHD was reported to be more common among the upper social classes. In New Zealand, as in other developed countries, this original trend across social classes was reversed during the past 40 years. In 1975-1977, a gradient across social class was observed for both CHD and cerebrovascular disease mortality, with the lowest social classes experiencing the highest mortality. This study has now been repeated for the period 1985-1987. Employed males aged 15-64 years were categorized by the Elley-Irving scale into six social classes. The overall age-standardized mortality rate from CHD declined over the ten-year period, from 163.0 to 121.7 per 100,000 person-years. Over the same period, however, the social class gradient for coronary mortality actually increased. The overall age-standardized mortality rate from cerebrovascular disease also declined over the ten-year period, from 25.9 to 17.7 per 100,000 person-years. A social class gradient for cerebrovascular mortality was present in both periods. In contrast to coronary mortality, however, the social class gradient diminished slightly over the ten-year period.

Noninvasive estimation of the instantaneous first derivative of left ventricular pressure using continuous-wave Doppler echocardiography

BACKGROUND

The complete continuous-wave Doppler mitral regurgitant velocity curve should allow reconstruction of the ventriculoatrial (VA) pressure gradient from mitral valve closure to opening, including left ventricular (LV) isovolumic contraction, ejection, and isovolumic relaxation. Assuming that the left atrial pressure fluctuation is relatively minor in comparison with the corresponding LV pressure changes during systole, the first derivative of the Doppler-derived VA pressure gradient curve (Doppler dP/dt) might be used to estimate the LV dP/dt curve, previously measurable only at catheterization (catheter dP/dt).

METHODS AND RESULTS

This hypothesis was examined in an in vivo mitral regurgitant model during 30 hemodynamic stages in eight dogs. Contractility and relaxation were altered by inotropic stimulation and hypothermia. The Doppler mitral regurgitant velocity spectrum was recorded along with simultaneously acquired micromanometer LV and left atrial pressures. The regurgitant velocity profiles were digitized and converted to VA pressure gradient curves using the simplified Bernoulli equation. The instantaneous dP/dt of the VA pressure gradient curve was then derived. The instantaneous Doppler-derived VA pressure gradients, instantaneous Doppler dP/dt, dP/dtmax, and -dP/dtmax were compared with corresponding catheter measurements. This method of estimating dP/dtmax from the instantaneous dP/dt curve was also compared with a previously proposed Doppler method of estimating dP/dtmax using the Doppler-derived mean rate of LV pressure rise over the time period between velocities of 1 and 3 m/sec on the ascending slope of the Doppler velocity spectrum. Both instantaneous Doppler-derived VA pressure gradients (r = 0.95, p less than 0.0001) and Doppler dP/dt (r = 0.92, p less than 0.0001) correlated well with corresponding measurements by catheter during systolic contraction and isovolumic relaxation (pooled data). The Doppler dP/dtmax (1,266 +/- 701 mm Hg/sec) also correlated well (r = 0.94) with the catheter dP/dtmax (1,200 +/- 573 mm Hg/sec). There was no difference between the two methods for measurement of dP/dtmax (p = NS). Although Doppler -dP/dtmax was slightly lower than the catheter measurement (961 +/- 511 versus 1,057 +/- 540 mm Hg/sec, p less than 0.01), the correlation between measurements by Doppler and catheter was excellent (r = 0.93, p less than 0.0001). The alternative method of mean isovolumic pressure rise (896 +/- 465 mm Hg/sec) underestimated the catheter dP/dtmax (1,200 +/- 573 mm Hg/sec) significantly (on average, 25%; p less than 0.001).

CONCLUSIONS

The present study demonstrated an accurate and reliable noninvasive Doppler method for estimating instantaneous LV dP/dt, dP/dtmax, and -dP/dtmax.

Undiminished social class mortality differences in New Zealand men

Social class mortality differences in New Zealand men aged 15-64 years have previously been examined for the period 1975-7. It was found that the lower social classes had mortality rates higher than the upper social classes with the mortality rate of the lowest class being approximately twice that of the highest class on a six category scale. The greatest relative social class differences were in men aged less than 35 years. The analysis has now been repeated for the period 1985-7. Mortality declined by 15% between 1975-7 and 1985-7, but the social class mortality differences were undiminished, and the mortality slope was actually slightly greater in the more recent time period. The primary significance of social class analyses is that they identify groups in the community which have an excess mortality that is potentially preventable. The findings of this study indicate that this potential has not been fully realised in New Zealand, since social class differences are undiminished despite the continuing decline in overall mortality.

Discovery of a metabolic pathway mediating glucose-induced desensitization of the glucose transport system. Role of hexosamine biosynthesis in the induction of insulin resistance

Based on our previous finding that desensitization of the insulin-responsive glucose transport system (GTS) requires three components, glucose, insulin, and glutamine, we postulated that the routing of incoming glucose through the hexosamine biosynthesis pathway plays a key role in the development of insulin resistance in primary cultured adipocytes. Two approaches were used to test this hypothesis. First, we assessed whether glucose-induced desensitization of the GTS could be prevented by glutamine analogs that irreversibly inactivate glutamine-requiring enzymes, such as glutamine:fructose-6-phosphate amidotransferase (GFAT) the first and the rate-limiting enzyme in hexosamine biosynthesis. Both O-diazoacetyl-L-serine (azaserine) and 6-diazo-5-oxonorleucine inhibited desensitization in 18-h treated cells without affecting maximal insulin responsiveness in control cells. Moreover, close agreement was seen between the ability of azaserine to prevent desensitization of the GTS in intact adipocytes (70% inhibition, ED50 = 1.1 microM), its ability to inactivate GFAT in intact adipocytes (64% inhibition, ED50 = 1.0 microM) and its ability to inactivate GFAT activity in a cytosolic adipocyte preparation (ED50 = 1.3 microM). From these results we concluded that a glutamine amidotransferase is involved in the induction of insulin resistance. As a second approach, we determined whether glucosamine, an agent known to preferentially enter the hexosamine pathway at a point distal to enzymatic amidation by GFAT, could induce cellular insulin resistance. When adipocytes were exposed to various concentrations of glucosamine for 5 h, progressive desensitization of the GTS was observed (ED50 = 0.36 mM) that culminated in a 40-50% loss of insulin responsiveness. Moreover, we estimated that glucosamine is at least 40 times more potent than glucose in mediating desensitization, since glucosamine entered adipocytes at only one-quarter of the glucose uptake rate, yet induced desensitization at an extra-cellular dose 10 times lower than glucose. In addition, we found that glucosamine-induced desensitization did not require glutamine and was unaffected by azaserine treatment. Thus, we conclude that glucosamine enters the hexosamine-desensitization pathway at a point distal to GFAT amidation. Overall, these studies indicate that a unique metabolic pathway exists in adipocytes that mediates desensitization of the insulin-responsive GTS, and reveal that an early step in this pathway involves the conversion of fructose 6-phosphate to glucosamine 6-phosphate by the first and rate-limiting enzyme of the hexosamine pathway, glutamine:fructose-6-phosphate amidotransferase.

Stomach cancer in New Zealand: time trends, ethnic group differences and a cancer registry-based case-control study

Stomach cancer trends in New Zealand were examined. Age-standardized mortality and incidence rates have declined over the past four decades, as in other countries. Rates have been consistently higher for men, and for Maori. A cancer registry-based case-control study of 1016 male stomach cancer cases and 19,042 male controls with other cancers was also conducted, to evaluate the relationships between stomach cancer and specific occupations. Adjustment was made for age, ethnicity, socioeconomic level, and smoking status. When 22 occupational groups were examined, adjusted odds ratios (ORs) and 95% confidence intervals (95% Cls) were elevated above unity for only one group: forestry workers (OR 1.83, 95% Cl 1.01-3.32). When two large, heterogeneous groups were broken down into 15 subgroups, adjusted ORs and 95% Cls elevated above unity were found for three sub-groups: grain millers and related workers; brewers, wine and beverage makers; and field crop workers. These findings may be because of the multiple comparisons and subgroup analyses undertaken. Men who had ever smoked cigarettes were found to have an increased stomach cancer risk compared to those who had never smoked (adjusted OR 1.36, 95% Cl 1.15-1.60).

The "natural history" of the transplanted lung: rates of pulmonary functional change in long-term survivors of heart-lung transplantation

Long-term pulmonary function in HLT is well preserved with no evidence of functional decline as a result of transplant "aging," providing the allografts remain free of complications. Long-term survivors with OB appear to be able to maintain adequate oxygenation despite the marked alterations of pulmonary function. The ability to preserve gas exchange at reasonable levels of oxygenation may be the factors permitting extended survival with OB for mean periods of 36.0 months or greater. Preliminary studies suggest that a declining FEF50/FVC, at a time when pulmonary function is normal, may be an index of impending airway disease. Physiologically, from a long-term point of view, HLT remains a viable option for selected patients with end-stage cardiopulmonary disease.