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Biomedical subjects

D Kaminski

Publications and source records attributed to D Kaminski.

At least 19 recordsLinked to original sources
PubMed2006

Observation of a liquid phase with an orthorhombic orientational order.

Using surface x-ray diffraction, we have determined the structure of liquid Bi monolayers on Cu(111) for a range of coverages. By combining diffuse scattering data from the liquid with information from the substrate scattering, the ordering properties of Bi have been fully determined. Even though the substrate is hexagonal, we find that the liquid does not show hexatic order but has an orthorhombic orientational order that occurs in three domains. Simultaneously, Bi has partial solidlike properties, even well above its melting point.

Journal Article↗
PubMed2003

New (sqrt3 xsqrt 3)R30 degrees phase of Pb on Ge(111) and its consequence for the melting transition.

Depending on the preparation method, we find two different structures of the Pb/Ge(111) system at a nominal coverage of 4 / 3 monolayer that exhibit different melting points. One is the well studied beta phase that melts at 270 degrees C, but the other is a new and metastable phase that melts at 330 degrees C. Using surface x-ray diffraction the atomic structure of both phases is found to be surprisingly similar. The difference in melting points can be explained by the distribution of the excess Pb present on the surface, which has a direct effect on the vacancy density. We propose a modified phase diagram, in which the melting temperature of the beta phase depends strongly on coverage.

Journal Article↗
PubMed2001

Diaphragm activation during exercise in chronic obstructive pulmonary disease.

Although it has been postulated that central inhibition of respiratory drive may prevent development of diaphragm fatigue in patients with chronic obstructive pulmonary disease (COPD) during exercise, this premise has not been validated. We evaluated diaphragm electrical activation (EAdi) relative to maximum in 10 patients with moderately severe COPD at rest and during incremental exhaustive bicycle exercise. Flow was measured with a pneumotachograph and volume by integration of flow. EAdi and transdiaphragmatic pressures (Pdi) were measured using an esophageal catheter. End-expiratory lung volume (EELV) was assessed by inspiratory capacity (IC) maneuvers, and maximal voluntary EAdi was obtained during these maneuvers. Minute ventilation (V E) was 12.2 +/- 1.9 L/min (mean +/- SD) at rest, and increased progressively (p < 0.001) to 31.0 +/- 7.8 L/min at end-exercise. EELV increased during exercise (p < 0.001) causing end-inspiratory lung volume to attain 97 +/- 3% of TLC at end-exercise. Pdi at rest was 9.4 +/- 3.2 cm H(2)O and increased during the first two thirds of exercise (p < 0.001) to plateau at about 13 cm H(2)O. EAdi was 24 +/- 6% of voluntary maximal at rest and increased progressively during exercise (p < 0.001) to reach 81 +/- 7% at end-exercise. In conclusion, dynamic hyperinflation during exhaustive exercise in patients with COPD reduces diaphragm pressure-generating capacity, promoting high levels of diaphragm activation.

Diaphragm↗
PubMed2000

Incidence of nocturnal desaturation while breathing oxygen in COPD patients undergoing long-term oxygen therapy.

STUDY OBJECTIVE: It is suggested that oxygen flow be increased by 1 L/min during sleep in COPD patients undergoing long-term oxygen therapy (LTOT) in order to avoid nocturnal desaturations. The purpose of this study was to investigate the occurrence of nocturnal desaturations while breathing oxygen in COPD patients receiving LTOT. SETTING: Inpatient/university hospital. PATIENTS: We studied 82 consecutive COPD patients. Their functional characteristics were as follows (mean +/- SD): FVC, 2.15 +/- 0.69 L; FEV(1), 0.87 +/- 0.33 L; PaO(2), 51.6 +/- 5 mm Hg; and PaCO(2), 47 +/- 8 mm Hg. MEASUREMENTS: Overnight pulse oximetry (PO) was performed twice: (1) while breathing air and (2) while breathing supplemental oxygen assuring satisfactory diurnal resting oxygenation (mean PaO(2) during oxygen breathing, 67 +/- 6 mm Hg; mean arterial oxygen saturation [SaO(2)] during oxygen breathing, 93%). RESULTS: PO performed while patients were breathing air showed a mean overnight SaO(2) of 82.7 +/- 6.7%. Patients spent 90% of the recording time with an SaO(2) of < 90%. While breathing oxygen, 43 patients (52.4%) remained well oxygenated. Their mean overnight SaO(2) while breathing oxygen was 94.4 +/- 2.1%, and time spent with saturation < 90% was 6.9 +/- 8.6%. Thirty-nine patients (47.6%) spent > 30% of the night with an SaO(2) of < 90% while breathing supplemental oxygen. Their mean overnight SaO(2) while breathing oxygen was 87.1 +/- 4.5%, and time spent with an SaO(2) of < 90% was 66.1 +/- 24.7% of the recording time. Comparison of ventilatory variables and daytime blood gases between both groups revealed statistically significantly higher PaCO(2) on air (p < 0.001) and on oxygen (p < 0. 05), and lower PaO(2) on oxygen (p < 0.05) in the group of patients demonstrating significant nocturnal desaturation. CONCLUSIONS: We conclude that about half of COPD patients undergoing LTOT need increased oxygen flow during sleep. Patients with both hypercapnia (PaCO(2) > or = 45 mm Hg) and PaO(2) < 65 mm Hg while breathing oxygen are most likely to desaturate during sleep.

Circadian Rhythm↗
PubMed1999

Synthetic pathways of gallbladder mucosal prostanoids: the role of cyclooxygenase-1 and 2.

Acute cholecystitis is associated with increased gallbladder prostanoid formation and the inflammatory changes and prostanoid increases can be inhibited by nonsteroidal anti-inflammatory agents. Recent information indicates that prostanoids are produced by two cyclooxygenase (COX) enzymes, COX-1 and COX-2. The purpose of this study was to determine the COX enzymatic pathway in gallbladder mucosal cells involved in the production of prostanoids stimulated by inflammatory agents. Human gallbladder mucosal cells were isolated from cholecystectomy specimens and maintained in cell culture and studied in comparison with cells from a well differentiated gallbladder mucosal carcinoma cell line. COX enzymes were evaluated by Western immunoblotting and prostanoids were measured by ELISA. Unstimulated and stimulated cells were exposed to specific COX-1 and COX-2 inhibitors. In both normal and transformed cells constitutive COX-1 was evident and in gallbladder cancer cells lysophosphatidyl choline (LPC) induced the formation of constitutive COX-1 enzyme. While not detected in unstimulated normal mucosal cells and cancer cells, COX-2 protein was induced by both lipopolysaccharide (LPS) and LPC. Unstimulated gallbladder mucosal cells and cancer cells produced prostaglandin E2 (PGE2) and prostacyclin (6-keto prostaglandin F1alpha, 6-keto PGF1alpha) continuously. In freshly isolated normal gallbladder mucosal cells, continuously produced 6 keto PGF1alpha was inhibited by both COX-1 and COX-2 inhibitors while PGE2 levels were not affected. Both LPS and LPC stimulated PGE2 and 6 keto PGF1alpha formation were blocked by COX-2 inhibitors in freshly isolated, normal human gallbladder mucosal cells and in the gallbladder cancer cells. The prostanoid response of gallbladder cells stimulated by proinflammatory agents is inhibited by COX-2 inhibitors suggesting that these agents may be effective in treating the pain and inflammation of gallbladder disease.

6-Ketoprostaglandin F1 alpha↗
PubMed1998

Mycobacterium szulgai osteomyelitis in an AIDS patient.

Mycobacterium szulgai is a scotochromogen mycobacterium that accounts for < 1% of all human isolates of non-tuberculous mycobacteria. We report the first case of osteomyelitis caused by Mycobacterium szulgai in an AIDS patient. Culture from tissue was needed for isolation and identification of the organism, which was initially misidentified as Mycobacterium gordonae. Susceptibility testing to a fluoroquinolone was carried out and is also reported here for the first time. This case demonstrates the pathogenic potential of M. szulgai in this setting, and illustrates the need to obtain tissue specimens for culture in infected immunosuppressed patients to make a specific microbiological diagnosis and institute appropriate therapy.

AIDS-Related Opportunistic Infections↗
PubMed1998

Partitioning of the elastic work of inspiration in patients with COPD during exercise.

During exercise, dynamic hyperinflation-induced intrinsic positive end-expiratory pressure (PEEPi) and decreased dynamic lung compliance (CL,dyn) of patients with chronic obstructive pulmonary disease (COPD) increase the elastic work of inspiration (Wi) more than would be predicted from the increase in tidal volume (VT). This contributes significantly to their exertional breathlessness. In 10 stable patients with COPD, the dynamic Wi was measured during incremental bicycle exercise to exhaustion. The total Wi was then partitioned into the portion required to overcome PEEPi (Wi,PEEPi) and nonPEEPi elastic load (Wi,nonPEEPi). The latter is used to overcome the increase in the total respiratory system elastance during inflation. From resting breathing to peak exercise, Wi more than doubled (p<0.001). This increase was largely due to Wi,PEEPi, which significantly rose from 1.7+/-0.3 to 5.3+/-0.8 L x cm H2O(-1) (p<0.001). In comparison, Wi,nonPEEPi increased from only 3.0+/-0.4 to 5.1+/-0.5 L x cm H2O(-1) (p<0.01). Consequently, Wi,PEEPi as a fraction of total Wi increased from 35.5+/-5.6 to 51.0+/-3.3% (p<0.02). In addition, the measured Wi,nonPEEPi at peak exercise, when expressed as a percentage of its value during resting breathing, was 25% more than that predicted from the increase in VT alone. Assuming a constant chest wall compliance, this can be attributed to the exercise-induced decrease in CL,dyn, which was 0.27+/-0.04 and 0.17+/-0.02 L x cm H2O(-1) (p<0.01), respectively, during resting breathing and peak exercise. In conclusion, the dynamic hyperinflation-induced intrinsic positive end-expiratory pressure is more important than the increase in tidal volume in raising the work of inspiration during exercise in patients with chronic obstructive pulmonary disease; the decrease in dynamic lung compliance plays a definite but less important role.

Adult↗
PubMed1997

Reliability of inspiratory capacity for estimating end-expiratory lung volume changes during exercise in patients with chronic obstructive pulmonary disease.

The inspiratory capacity (IC) maneuver is increasingly used to monitor exercise-induced dynamic hyperinflation in patients with COPD. However, the reliability of this method in patients with COPD exercising to symptom limitation has not been systematically studied and presented. The purpose of the present study was therefore to evaluate the reliability of the IC maneuver in assessing changes in end-expiratory lung volume (EELV) by assessing the pressure developed during IC maneuvers, in patients with COPD during incremental bicycle exercise to exhaustion. Fifteen patients with stable COPD performed bicycle exercise to symptom limitation. During the experiment, the patients performed IC efforts during resting breathing and at the end of each exercise work load. Esophageal pressure (Pes) measured at peak inspired volume plateau (zero flow) was -13.5 +/- 1.9 and -13.4 +/- 1.9 cm H2O (p = 0.79) during IC maneuvers at resting breathing and during the final exercise work load, respectively. When the Pes values at the peak inspired volume plateau during IC efforts at each exercise level were expressed as a percentage of those during resting breathing, the great majority of the ratios were above 90% with the lowest at 84%, and these ratios were independent of exercise intensity. Despite a constant Pes during IC, there was a progressive decrease in IC with increasing exercise work load in most patients, suggesting an increase in EELV. At the highest exercise work load achieved, delta EELV calculated as the decrease in IC was 0.26 +/- 0.06 L (p < 0.001). We conclude that repeated IC maneuver is a simple and reliable method for estimating EELV changes during exercise to exhaustion in patients with COPD.

Exercise↗
PubMed1997

Inspiratory muscle mechanics of patients with chronic obstructive pulmonary disease during incremental exercise.

Inspiratory muscles are weak and contribute to exercise limitation in chronic obstructive pulmonary disease (COPD). Differential inspiratory pressure contributions from the diaphragm and inspiratory rib cage muscles (RCMs) during exercise in patients with COPD patients are insufficiently described. We measured, in 16 patients with COPD, the global inspiratory muscle pressure (delta Pmus) and transdiaphragmatic pressure (delta Pdi) during an incremental bicycle exercise to exhaustion. The pressures needed to overcome the elastic load were further partitioned into portions for overcoming the PEEPi-imposed inspiratory threshold load (before the beginning of inspiratory flow) and for inflating the respiratory system (between the beginning and end of inspiratory flow). The delta Pdi/delta Pmus ratio was used to quantify the pressure contribution from RCMs relative to that from the diaphragm for a given inspiratory effort. We observed that in patients with COPD during exercise (1) there is a progressive increase in total inspiratory pressure contribution from RCMs relative to that of the diaphragm, and the magnitude of this increase appears to depend on the RCMs reserves during resting breathing; (2) most of the diaphragmatic pressure contribution occurs before the beginning of inspiratory flow, to overcome the PEEPi-imposed inspiratory threshold load; (3) RCMs pressure contribution predominates during the period of inspiratory flow once PEEPi is neutralized, not only for overcoming the elastic load caused by increased tidal volume, but also for compensating for the diaphragmatic pressure contribution during this interval that was gradually lost with increasing exercise work load.

Exercise Test↗
PubMed1997

Pulmonary thromboembolism.

Pulmonary embolism (PE) is a serious complication of chronic obstructive pulmonary disease (COPD). Retrospective studies on patients with COPD treated in the intensive care unit (ICU) were performed to determine: 1) the frequency of PE; 2) the clinical course of PE in cases of COPD in the ICU; and 3) the frequency of PE as a cause of death in the studied group. The frequency of PE was 10.9% in COPD patients. In the group analysed, clinical presentation of PE was characterized by acute severe, life-threatening complications leading to death in 86.7% of cases. PE was the most frequent cause of death (40.6%) in COPD patients in the ICU. The results of treatment of pulmonary embolism in chronic obstructive pulmonary disease are poor and mortality in this group of patients is very high. We believe that improvement of management can be achieved by antithromboembolic prophylaxis, which should be instituted as soon as possible in all patients with chronic obstructive pulmonary disease in the intensive care unit.

Cause of Death↗
PubMed1996

Prognostic value of the monoethylglycinexylidide liver function test in assessing donor liver suitability.

BACKGROUND: Liver graft assessment prior to transplantation continues to be controversial. Various donor organ parameters must be evaluated to ensure that the transplanted organ will function and that the number of organs discarded will be minimized. Recent attempts to quantify liver function have utilized the metabolism of lidocaine to monoethylglycinexylidide (MEGX), and the MEGX test has been employed to evaluate the functional characteristics of donor livers prior to transplantation, with conflicting results. OBJECTIVE: To ascertain the role of quantitating the metabolic rate of lidocaine in predicting the results of liver transplantation. METHODS: Consecutive liver donors (N = 37) underwent quantitation of the amount of lidocaine converted to MEGX at 15 minutes. The donor patients were divided arbitrarily into efficient and poor lidocaine metabolizers, and the results of liver transplantation were evaluated. RESULTS: Patients who received livers that produced MEGX values of 80 ng/mL or less in 15 minutes had no definable alteration in transplantation outcome compared with patients who received livers that were more efficient lidocaine metabolizers. In a collected series, 46 patients who received livers that produced MEGX values of 80 ng/mL or less had a 1-month graft survival rate of 89% (41/46), while 74 patients who received livers that produced MEGX values greater than 80 ng/mL had a 1-month graft survival rate of 86% (64/74). CONCLUSIONS: The MEGX test had no practical utility in predicting liver graft functional status.

Humans↗
PubMed1993

Modulation of serotonin binding sites in the brain of the Djungarian hamster, Phodopus sungorus, during adaptation to a short photoperiod.

During the physiological adaptation of the Djungarian hamster, Phodopus sungorus, to a short photoperiod in autumn the modulation of specific serotonin (5-HT) binding sites of synaptic membranes was investigated in two brain regions, i.e. cerebral cortex and basal brain (CNS without cerebral cortex, cerebellum, pineal gland, and spinal cord). The radioligands [3H]5-HT and [3H]ketanserin were used to characterize total 5-HT1 and 5-HT2 binding sites, respectively. An increase of 5-HT1 and 5-HT2 binding sites was observed in both brain regions within 14 days after reduction of the photoperiod from a 14:10 h light/dark (l/d) cycle to an 8:16 h l/d cycle. The increase was still present after 56 days of the short photoperiod. Binding kinetics assayed after 4 days of the short photoperiod show that maximal specific binding of [3H]5-HT and [3H]ketanserin was increased, while dissociation constants (KD) were not changed. The membrane anisotropy of synaptic membranes, measured by fluorescence polarization, was reduced transiently during the early part of the adaptation. Neither the phospholipids nor the mole ratio of cholesterol to phospholipids were significantly affected by adaptation to short photoperiod. The results suggest an important role of the central nervous 5-HT system in the physiological adaptation of the Djungarian hamster to a short photoperiod.

Adaptation, Physiological↗
PubMed1991

Sulfation and glucuronidation of acetaminophen by cultured hepatocytes reproducing in vivo sex-differences in conjugation on Matrigel and type 1 collagen.

The sulfate and glucuronide conjugation of acetaminophen (APAP) by hepatocytes cultured on Matrigel or type 1 collagen was compared to APAP metabolism in vivo. The metabolic fate of low (15 mg/kg), medium (125 mg/kg), and high (300 mg/kg) doses of APAP injected intraperitoneally were determined in male and female rats. Males excreted more APAP as the sulfate conjugate than females, which correlated with the twofold greater APAP sulfotransferase activity in the male vs. females (301 +/- 24 vs. 156 +/- 18 pmol.mg-1 protein.min-1). Also, as sulfate conjugation became saturated, there was a dose-related shift in APAP metabolism from sulfate to glucuronide conjugation in both sexes. After death, the livers of the same animals were perfused with collagenase and the hepatocytes cultured in modified Waymouth's medium on either Matrigel or rat-tail collagen, with various doses of APAP (0, 0.125, 0.25, 0.5, and 1.0 mM). Sex differences in APAP sulfation and glucuronidation persisted in culture for up to 4 days, with sulfation predominating in the male similar to in vivo. With increasing APAP concentration (dose), there was a saturation of sulfate conjugation and a shift to glucuronidation as observed in vivo. Sex differences in APAP sulfation and glucuronidation were no longer significant by Day 4 in culture. Sulfation, and to a lesser extent, glucuronidation, were more stable on Matrigel than collagen. We concluded that APAP metabolism of freshly isolated hepatocytes could replicate in vivo sex differences in conjugation, and that Matrigel was superior to collagen as substrate.

Acetaminophen↗
PubMed1982

Evaluation of various techniques to monitor intragastric pH.

Recent reports emphasized the importance of maintenance of a high intragastric pH to prevent gastric mucosal bleeding in acutely ill patients. In this study gastric fluid pH determinations were compared with determinations obtained using an intragastric pH electrode. There was poor correlation between pH determinations obtained by a bare intragastric electrode in contact with the mucosa and pH determinations on fluid aspirated from the stomach. During cimetidine administration mucosal and fluid determinations correlated well, whereas during antacid administrations correlated well, whereas during antacid administration mucosal pH was significantly lower than gastric fluid pH. These results suggest that during antacid administration pH determinations on gastric contents with pH paper may not accurately reflect the pH at the mucosal surface.

Antacids↗
PubMed1980

Spontaneous and shock-associated ischemic colitis.

Ischemic changes in the colon that progress to gangrene present diagnostic and therapeutic difficulties associated with poor survival. During the past 10 years, 36 patients with colonic ischemia were treated. Two clinical groups were evident. The spontaneous ischemic colitis group (type I) included 17 patients who were well before the onset of gastrointestinal symptoms. The cause of type I ischemic colitis is not apparent; it is attributed to occlusive or nonocclusive ischemia. The other group (type II) included 19 patients who developed ischemia of the colon associated with shock secondary to various disease processes. Radiographic evidence of distended bowel correlated well with full-thickness necrosis as determined clinically or pathologically. Twenty-one patients died, for a mortality rate of 58 percent. While full-thickness gangrene was fatal in 71 percent of the patients, mucosal necrosis only was associated with an 88 percent survival rate. The results of treatment should improve with an increased awareness of ischemic colitis, earlier appropriate operative intervention, and more appropriate use of ileostomy and colostomy.

Aged↗
PubMed1980

Effect of Treponema pallidum-infected testis supernatants on the cellular response of normal rabbit lymphocytes.

This report presents evidence indicating that both Treponema pallidum and the T. pallidum-free supernatant from T. pallidum-infected rabbit testes exert an immunosuppressive effect on the spontaneous proliferation and mitogenic response of normal rabbit lymphocytes. This effect seemed to be on the level of clonal expansion since antigenic recognition and blastogenic factor production occurred in spite of the presence of the immunosuppressive substance(s). The implication of this finding for T. pallidum multiplication in rabbit testes is discussed.

Animals↗
PubMed1977

Evidence for additional mediator in prostaglandin-induced choleresis.

PGA1 and PGF2alpha were administered to isolated perfused porcine and canine livers to determine whether these hormones could induce hepatic choleresis. PGA1 (25 microgram/kg/10 min) decreased portal venous resistance, but had no effect on bile flow, oxygen, pyruvate, or lactate consumption in canine livers. PGF2alpha increased portal venous resistance and weight gain while decreasing bile flow and oxygen consumption in canine livers. At high doses (50 microgram/kg/10 min) these effects resulted in irreversible outflow block. At low doses (5 microgram/kg/10 min) these trends were reversible. Porcine livers did not exhibit the outflow block syndrome after PGF2alpha administration (100 microgram/kg/10 min); however, choleresis was not observed. Thus, the in-vivo choleretic effects of prostaglandins previously reported are probably mediated partially or wholly by extrahepatic release of other hormones, neurological stimulation or alterations in mesenteric blood flow.

Animals↗