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Biomedical subjects

R M Rogers

Publications and source records attributed to R M Rogers.

At least 37 records · Page 2Linked to original sources
PubMed1996

Lung reduction surgery for emphysema.

Lung reduction surgery, a procedure that entails removal of portions of the most diseased lung tissue in patients with diffuse emphysema, has been resurrected based on advances in surgical technique, radiographic imaging, and pulmonary physiologic assessment. We outline potential mechanisms for improvement in pulmonary mechanics, gas exchange, pulmonary vascular function, and exercise tolerance following surgery. Available literature is reviewed, and patterns that are beginning to emerge with respect to optimal surgical approach and patient selection criteria are presented. Early results suggest that this procedure offers real hope to our patients; however, long-term follow-up studies will be necessary to define its ultimate utility.

Exercise Tolerance↗
PubMed1996

Elevated TNF-alpha production by peripheral blood monocytes of weight-losing COPD patients.

The inflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha) and interleukin-1-beta (IL-1 beta), have been associated with accelerated metabolism and protein turnover following exogenous administration in normal humans. We hypothesized that these inflammatory cytokines might contribute to the weight-losing process in patients with chronic obstructive pulmonary disease (COPD). COPD patients were identified prospectively as "weight losers" (WL; n = 10) if they reported > 5% weight loss during the preceding year or as "weight stable" (WS; n = 10) if their body weight fluctuated < or = 5%. Age-matched healthy volunteers were selected as the control group (C; n = 13). Monocytes were isolated from a peripheral blood sample, cultured, and exposed to lipopolysaccharide (LPS). The concentration of TNF-alpha and IL-1 beta in the monocyte supernatant was measured using a four layer enhanced ELISA. No significant difference in LPS-stimulated IL-1 beta production was found in the three study populations. However, LPS-stimulated TNF-alpha production (mean [range] ng/ml) by monocytes was significantly higher in the WL COPD patients (20.2 [6.3 to 44.8]), compared with WS patients (6.9 [1.5 to 16.6]), and C subjects (5.7 [0 to 61.8]). This difference was not maintained at 6 mo follow-up in the absence of ongoing weight loss. Definition of a causal relationship between TNF-alpha production and weight loss will require further understanding of the relationship between energy metabolism and TNF-alpha production in these patients.

Aged↗
PubMed1993

Mechanisms of weight loss in chronic obstructive pulmonary disease.

The COPD patient population is susceptible to the onset of weight loss. The presence of this feature carries significant negative prognostic implications. Whether weight loss contributes to or is simply a marker of disease severity remains to be determined. Weight loss appears to result from an imbalance of metabolic demand and supply. The factors which produce this imbalance require further investigation.

Energy Intake↗
PubMed1992

Effects of growth hormone on diaphragmatic recovery from malnutrition.

A 25% weight loss was induced in adult Fisher 344 rats by nutritional deprivation. Subsequently, normal feeding was resumed. Refed animals were divided into three groups and received recombinant human growth hormone (rhGH) injections during 5 wk of refeeding, saline injections during 5 wk of refeeding, or 9 wk of refeeding without injections. The effects of nutritional deprivation and the various refeeding protocols on the cross-sectional areas (CSA) of each of the four types of myofibers [typed immunohistochemically with antibodies against four myosin heavy chain (MHC) isoforms known to be present in the rat diaphragm] were determined. Malnutrition decreased the CSA of myofibers containing MHC2X, MHC2B, and MHC2A (i.e., fast myofibers), with the greatest effect on muscle mass being due to the atrophy of fibers containing MHC2X. Fibers containing MHC beta/slow failed to undergo malnutrition-induced atrophy. Whereas refeeding for 5 wk in the absence of rhGH allowed the recovery of CSA of fibers containing MHC2A, fibers containing MHC2B and MHC2X remained smaller than fibers of similar type in control animals. In contrast, 5 wk of refeeding supplemented with rhGH returned all fiber CSAs to control values. Even when refeeding alone was extended to 9 wk to allow for weight stabilization, the CSA of the fibers containing MHC2B and MHC2X remained smaller than similar fibers in control muscle. Serum insulin-like growth factor, a marker of malnutrition (R. Reeves and J. Elders, J. Nutr. 109: 613-620, 1979), was significantly decreased after nutritional deprivation and returned to normal after 5 wk of refeeding and GH supplementation.

Animals↗
PubMed1992

Is loss of body weight in chronic obstructive pulmonary disease patients with emphysema secondary to low tissue oxygenation?

The available clinical information to date does not support the hypothesis that tissue oxygen debt is the primary cause of the wasting process in the chronic obstructive pulmonary disease (COPD) patient population. However, this should not deter the 'believers' of the hypothesis from further investigation. The information outlined above supports the need for reconsideration of this clinical problem. Tissue oxygen requirements and utilization is a complex interplay of multiple variables. Likewise, the assessment of nutritional status in the setting of oxygen therapy is complicated by shifts in body fluid compartments independent of changes in the fat-free mass (FFM). Utilization of newer techniques will be required to resolve the contribution of low tissue oxygenation to the wasting process. The continued development of noninvasive methods for the assessment of tissue metabolism, cardiac function, and tissue energy requirements will allow investigators to further clarify the relationship between tissue oxygenation and metabolism in patients with COPD. Clinical trials designed to examine this issue must recognize the multiple effects of oxygen on all aspects of nutrient utilization, including caloric intake, needs, and tissue delivery. Failure to address all aspects of this system will lead to continued debate regarding the etiology of weight loss in the COPD patient population.

Clinical Trials as Topic↗
PubMed1992

Pulmonary function abnormalities in chronic severe cardiomyopathy preceding cardiac transplantation.

Pulmonary function data, including diffusing capacity, were evaluated in 56 patients with chronic severe cardiomyopathy before heart transplantation. Cardiac catheterization data were used to describe the relationship between cardiac and pulmonary function. Of 56 patients 44 had some abnormality in pulmonary function. The majority, 30 of 56, had a restrictive impairment alone. Of 28 patients in whom diffusing capacity was measured, 64% had a diffusion impairment. There was no association of pulmonary function impairment with type of cardiomyopathy or smoking history. Pulmonary capillary wedge pressure correlated positively with DLCO, but not with FVC or TLC. Cardiac index and ejection fraction did not correlate with diffusing capacity. This precardiac transplantation cardiomyopathy patient group demonstrated frequent pulmonary function abnormalities not previously recognized.

Adult↗
PubMed1992

Physiologic effects of oral supplemental feeding in malnourished patients with chronic obstructive pulmonary disease. A randomized control study.

The association between severe nutritional depletion and chronic obstructive pulmonary disease (COPD) has long been recognized. A potential therapeutic benefit to nutritional support was previously suggested by us in a pilot investigation. Subsequent studies have reported conflicting results regarding the role of nutritional therapy in this clinical population. We report a randomized controlled study of nutritional therapy in underweight patients with COPD that combines an initial inpatient investigation (controlled nutritional support) with a prolonged outpatient follow-up interval. Provision of adequate calorie and protein support, adjusted to metabolic requirements, resulted in weight gain (intervention = +2.4 kg versus control -0.5 kg), improved handgrip strength (intervention = +5.5 kg-force versus control -6.0 kg-force), expiratory muscle strength (intervention = +14.9 cm H2O versus control -9.2 cm H2O), and walking distance (intervention = +429 feet versus control -1.0 foot). Inspiratory muscle strength was also improved (intervention = +11.4 cm H2O versus control +4.8 cm H2O) although this did not quite reach statistical significance. We conclude that provision of adequate nutrient supply under controlled conditions results in significant clinical improvements in the COPD patient population. However, the intervention is costly, time-intensive, and of limited therapeutic magnitude. More detailed work of alternative outpatient strategies combined with additional rehabilitative measures is indicated to delineate the full therapeutic potential of nutritional support for this clinical population.

Basal Metabolism↗
PubMed1991

Serum and lavage lactate dehydrogenase isoenzymes in pulmonary alveolar proteinosis.

Pulmonary alveolar proteinosis (PAP) is a rare disease characterized by the accumulation of lipoproteinaceous material in the alveolar space. Serum lactate dehydrogenase (LDH) has been noted to be elevated in patients with PAP in previous studies. We sought to extend this observation in a series of patients with PAP by looking at total serum LDH concentrations and LDH isoenzyme fractions measured before and after whole lung lavage. Total LDH and LDH isoenzymes were also determined in the lavage effluent. Total serum LDH was elevated before lavage in 10 of 16 patients. Prelavage serum LDH and prelavage alveolar-arterial O2 gradient showed a significant correlation (r = 0.62, p less than 0.05). A decrease in serum LDH was found after lavage in all patients in whom postlavage data was available (paired t test, p less than 0.01, n = 11), although the magnitude of this decrease varied considerably. The isoenzyme pattern before lavage was isomorphic, and this pattern was unchanged after whole lung lavage. This was in marked contrast to the LDH isoenzyme pattern observed in the lavage effluent, which showed a lower percent LDH1 and LDH2 and a higher percent LDH3, LDH4, and LDH5 when compared with the corresponding prelavage isoenzyme percentages for serum (unpaired t test, p less than 0.001). There was no correlation between the total serum LDH concentration and the total lavage LDH concentration. These data confirm that elevated serum LDH is a common finding in PAP. Furthermore, the LDH elevation found consistently in the alveolar fluid points to this as the source of the serum LDH.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchoalveolar Lavage Fluid↗
PubMed1990

Inductance plethysmography measurement of CPAP-induced changes in end-expiratory lung volume.

The respiratory inductance plethysmograph (RIP) has recently gained popularity in both the research and clinical arenas for measuring tidal volume (VT) and changes in functional residual capacity (delta FRC). It is important however, to define the likelihood that individual RIP measurements of VT and delta FRC would be acceptably accurate (+/- 10%) for clinical and investigational purposes in spontaneously breathing individuals on continuous positive airway pressure (CPAP). Additionally, RIP accuracy has not been compared in these regards after calibration by two commonly employed techniques, the least squares (LSQ) and the quantitative diagnostic calibration (QDC) methods. We compared RIP with pneumotachographic (PTH) measurements of delta FRC and VT during spontaneous mouth breathing on 0-10 cmH2O CPAP. Comparisons were made after RIP calibration with both the LSQ (6 subjects) and QDC (7 subjects) methods. Measurements of delta FRC by RIPLSQ and RIPQDC were highly correlated with PTH measurements (r = 0.94 +/- 0.04 and r = 0.98 +/- 0.01 (SE), respectively). However, only an average of 30% of RIPQDC determinations per subject and 31.4% of RIPLSQ determinations per subject were accurate to +/- 10% of PTH values. An average of 55.2% (QDC) and 68.8% (LSQ) of VT determinations per subject were accurate to +/- 10% of PTH values. We conclude that in normal subjects, over a large number of determinations, RIP values for delta FRC and VT at elevated end-expiratory lung volume correlate well with PTH values. However, regardless of whether QDC or LSQ calibration is used, only about one-third of individual RIP determinations of delta FRC and one-half of two-thirds of VT measurements will be sufficiently accurate for clinical and investigational use.

Functional Residual Capacity↗
PubMed1990

Intensity versus type of affect elicited by dissociative cognitions in moderating acute pain.

75 undergraduates were trained to use cognitions that elicited either high or low pleasure, high or low fear, or received an expectancy manipulation. Groups high in pleasure showed greater tolerance for pressure pain than other treatment groups but did not differ from expectancy; differences were not found on discomfort ratings. Results were not attributable to differential compliance with instructions, perceived effectiveness of cognitions used, or the number of cognitions used. The percentage of time during stimulation that assigned cognitions were used appeared to mediate tolerance. Expectations for improved tolerance elicited by appealing cognitions and compelling placebos may also mediate tolerance.

Adolescent↗
PubMed1990

Nutritional assessment and support in chronic obstructive pulmonary disease.

Malnourished COPD patients demonstrate energy requirements significantly above predicted needs especially during activity. Recognition of this altered metabolic state is essential to the design of any nutritional intervention program. This factor alone, however, cannot explain the wasting syndrome observed in these patients. The elevated demands appear to combine with recognized factors which act to limit caloric intake. Nutritional repletion with calorie and protein supply proportional to demand is associated with weight gain, nitrogen retention, and improvement in physiologic parameters of muscle strength. Greater success of outpatient nutritional repletion in this population is dependent on alternative feeding strategies to deal with those symptoms which limit caloric intake, especially during a disease exacerbation. Future clinical research must explore these strategies before an adequate assessment of the risk and cost-benefit ratio of nutritional intervention can be determined. Additional work is indicated in techniques to identify those patients who would benefit from calorie supplementation as well as techniques to monitor the response of these individuals. Information gathered from the continued study of this population of stable outpatients with COPD will have wide application to the entire COPD patient population. This includes those patients with respiratory failure on mechanical ventilation, where numerous complicating factors makes the study of nutritional intervention and respiratory muscle function difficult.

Body Constitution↗
PubMed1989

Daily living with COPD. Self-help skills to improve functional ability.

Although patients with chronic obstructive pulmonary disease (COPD) experience many problems as a result of their disease, they can use numerous strategies to maximize functional ability and maintain health. Patients with COPD should be encouraged to learn more about their disease and use commonsense approaches to management. Referral to a pulmonary rehabilitation program that offers comprehensive assessment, individualized treatment, and access to support groups is also valuable. Rehabilitation programs often result in an improved capability for daily activities and a better quality of life.

Activities of Daily Living↗
PubMed1989

Improvement in alveolar macrophage migration after therapeutic whole lung lavage in pulmonary alveolar proteinosis.

Pulmonary alveolar proteinosis (PAP) is a rare disease characterized by the accumulation of lipoproteinaceous material in the alveolar space. Alveolar macrophages (AM) in this disease have been noted in the past to have abnormally decreased function. It is not known whether these abnormalities are reversible with treatment of the disease. In this study, the effect of therapeutic whole lung lavage (WLL) on AM migration in four patients with PAP was determined. Standard segmental bronchoalveolar lavage (BAL) was performed 1 day before and 6 days after WLL. AM recovered by BAL were assayed for migratory response to N-formyl-methionyl phenylalanine (FMP) and endotoxin-activated human serum (EAHS). As expected, migration toward both stimuli was decreased before WLL compared to a group of normal controls. After WLL, AM migration toward both stimuli was not only greater than before the WLL but also was greater than normal. In one patient, serial BAL over a period of 18 months showed a marked decline in AM migration coincident with a clinical relapse of the disease. Thus, the defect in AM function found in PAP is reversible with WLL but can recur if clinical remission is not sustained.

Cell Migration Inhibition↗
PubMed1989

Body weight in chronic obstructive pulmonary disease. The National Institutes of Health Intermittent Positive-Pressure Breathing Trial.

This study reviews the relationship between body weight, pulmonary function, and survival in the recent clinical trial of intermittent positive pressure breathing (IPPB). We related body weight, expressed as a percent of the ideal (%IBW), to the numerous other features of the disease recorded in this data set. Body weight was directly related to FEV1 (p = 0.0001), so that all subsequent analyses of body weight had to first consider FEV1. Mortality appeared to be influenced by body weight independent of FEV1. In patients with %FEV1 less than 35, mortality increased with decreasing body weight (p = 0.093), and this relationship was stronger in patients with %FEV1 35 to 47 (p = 0.048) and even stronger in patients with %FEV1 greater than 47 (p = 0.007). After adjusting for FEV1, body weight was a powerful positive correlate with exercise capacity (p = 0.0001). Body weight was also inversely related to %TLC (p = 0.0408) after adjusting for FEV1. Body weight was a powerful predictor of diffusing capacity (p = 0.0001) in patients with the same FEV1. These results support the hypothesis that factors related to nutritional status are an independent influence on the course of COPD.

Adult↗