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Biomedical subjects

K Martin

Publications and source records attributed to K Martin.

At least 127 records · Page 7Linked to original sources
PubMed1997

Relocation stress syndrome: the case of palliative care patients.

Transfer of patients from palliative care services to nursing homes is necessary at present when a patient is relatively stable, but does not have adequate support systems at home. With the ageing of the population and the increasing incidence of cancer, the need for inpatient palliative care beds is growing with corresponding pressure for patients to be transferred to nursing homes. Transfer to a nursing home in the general population has been described extensively in the gerontology literature where a critical early phase of relocation has been identified by a high incidence of morbidity and mortality. The vulnerability of terminally ill patients means that they are at increased risk of suffering from stress associated with a transfer. The prognosis of a patient may be shorter than the time required for adjustment to the patient's new home. The issues surrounding transfer of palliative care patients to nursing homes and possible strategies designed to reduce distress associated with transfers are explored.

Adaptation, Psychological↗
PubMed1997

Effect of controlled extracorporeal blood cooling on ultrafiltration-induced blood volume changes during hemodialysis.

Considerable amounts of heat may be lost or gained through the extracorporeal circuit during hemodialysis and influence the hemodynamic stability of the dialysis patient. The effects of two levels of extracorporeal heat flux (Jtherm in W) on blood pressures and ultrafiltration-induced blood volume changes were studied in eight patients on conventional hemodialysis. Treatments were controlled automatically for mild to medium Jtherm of either -13.4 +/- 3.3 W (group A) or -30.2 +/- 3.7 W (group B) (1 W = 1 J/s = 3.6 kJ/h = 0.239 cal/s = 0.86 kcal/h) and repeated once. Values are given as mean +/- SD. With low blood flows (Qb = 251 +/- 21 ml/min), dialysate temperatures were automatically set at 37.3 +/- 0.3 degrees C (group A) and 35.3 +/- 0.2 degrees C (group B) for the two levels of Jtherm, respectively. Arterial blood temperatures increased by 0.4 +/- 0.4 degree C with mild extracorporeal cooling (group A), whereas arterial blood temperatures slightly decreased by -0.1 +/- 0.4 degree C in the group with medium negative heat flux (group B) (P < 0.01). Blood pressures tended to drop in the warm dialysate group and to remain unchanged in the cool dialysate group (P = NS). Relative blood volume changes calculated from on-line ultrasonic blood measurements were significantly larger with cool (-12.8 +/- 8.3 vol%) than with warm (-7.2 +/- 5.5 vol%, P < 0.05) dialysate, indicating reduced fluid removal from peripheral body compartments during cool hemodialysis ultrafiltration. Despite the larger reduction in intravascular volume, intradialytic hemodynamic stability was maintained with extracorporeal cooling and cool dialysate prescription.

Aged↗
PubMed1997

A volumetric approach to virtual simulation of functional endoscopic sinus surgery.

Advanced display technologies have made the virtual exploration of relatively complex models feasible in many applications. Unfortunately, only a few human interfaces allow natural interaction with the environment. Moreover, in surgical applications, such realistic interaction requires real-time rendering of volumetric data-placing an overwhelming performance burden on the system. We report on a collaboration of an interdisciplinary group developing a virtual reality system that provides intuitive interaction with volume data by employing real-time volume rendering and force feedback (haptic) sensations. We describe our rendering methods and the haptic devices and explain its utility of this system in the real-world application of Endoscopic Sinus Surgery (ESS) simulation.

Computer Simulation↗
PubMed1997

Metabolic correlates of obesity and radiographic features of knee osteoarthritis: data from the Baltimore Longitudinal Study of Aging.

OBJECTIVE: To examine the relationship between metabolic correlates of obesity and radiographic knee osteoarthritis (OA). METHODS: We included 464 Caucasian men and 275 Caucasian women aged 40 years and above who were participants in the Baltimore Longitudinal Study of Aging. Subjects had bilateral anteroposterior standing knee radiographs read for features of OA using Kellgren-Lawrence scales. Resting blood pressure, fasting lipids, 2 h oral glucose tolerance test, and anthropometric measurements were obtained at the same visit as the knee radiograph. Metabolic correlates of obesity were compared between subjects with Kellgren-Lawrence grade > or = 2 (definite knee OA) and grade 0 (normal radiograph) by sex. RESULTS: Both men and women with knee OA had higher unadjusted systolic blood pressure than those with normal knee radiographs; unadjusted measures of glucose metabolism and lipids did not vary by presence of knee OA in men or women. After adjustment for age and obesity, systolic blood pressure did not vary by presence of knee OA in men. While women with knee OA did have higher adjusted mean systolic blood pressure than women with normal radiographs (127 +/- 2.4 vs 120 +/- 2.2 mm Hg; p = 0.04), both values were within normal range. Unexpectedly, men with knee OA had lower adjusted mean 2 h glucose levels compared to men without OA (7.5 +/- 0.2 vs 8.4 +/- 0.2 mmol/l; p = 0.01). Other adjusted variables did not differ by presence of knee OA. CONCLUSION: These data do not support the hypothesis that metabolic correlates of obesity are independently associated with radiographic knee OA after adjustment for age and obesity.

Adult↗
PubMed1997

[Risk management to control increased and more costly malpractice suits].

Considerable increase of premium for risk-insurance demands now risk management (RM) in German hospitals. RM is more than quality management and has other goals. The method we are using to analyse the risk in hospitals is given in detail. By this way we cover the main groups of potential personal damage of patients and reasons and fundamentals to sue the hospital. There is no total quality management (TQM) in hospitals without RM in the medical field. RM can be successful only with the awareness of medical and nursing staff for risks and liability claims. In our experience there is a lot of potential damages and sources of liability demands even in hospitals which seem to be well managed.

Cost Control↗
PubMed1996

Long-term potentiation is reduced in mice that are doubly mutant in endothelial and neuronal nitric oxide synthase.

Nitric oxide (NO) has been implicated in hippocampal long-term potentiation (LTP), but LTP is normal in mice with a targeted mutation in the neuronal form of NO synthase (nNOS-). LTP was also normal in mice with a targeted mutation in endothelial NOS (eNOS-), but LTP in stratum radiatum of CA1 was significantly reduced in doubly mutant mice (nNOS-/eNOS-). By contrast, LTP in stratum oriens was normal in the doubly mutant mice. These results provide the first genetic evidence that NOS is involved in LTP in stratum radiatum and suggest that the neuronal and endothelial forms can compensate for each other in mice with a single mutation. They further suggest that there is also a NOS-independent component of LTP in stratum radiatum and that LTP in stratum oriens is largely NOS independent.

Animals↗
PubMed1996

Repression of RNA polymerase III transcription by the retinoblastoma protein.

Transcription by RNA polymerase (pol) III is under cell-cycle control, being higher in S and G2 than in G0 and early G1 phases. Many transformed cell types have elevated pol III activity, presumably to sustain sufficient protein synthesis for unrestrained growth. The retinoblastoma tumour-suppressor protein (Rb) restricts cellular proliferation, and is often found mutated in transformed cells. Here we demonstrate that Rb can repress the level of transcription from pol III templates both in vitro and vivo. Analysis of Rb-deficient SAOS2 cells and primary fibroblasts from Rb-/- mice demonstrates elevated levels of pol III activity in the absence of functional Rb protein. Rb-induced repression of pol III activity is alleviated by mutations in the Rb pocket domain that occur naturally in tumours, and by viral transforming proteins that bind and inactivate Rb. These results implicate repression of pol III transcription as a mechanism for Rb-induced growth arrest, and suggest that restraining protein biosynthesis may be important in the prevention of tumour development.

Adenovirus E1A Proteins↗
PubMed1996

The effects of pentoxifylline on circulating adhesion molecules in critically ill patients with acute renal failure treated by continuous veno-venous hemofiltration.

OBJECTIVE: Circulating adhesion molecules appear to be excellent markers of endothelial activation in critically ill patients. Pentoxifylline (PTX) may limit sequelae of inflammation and subsequent endothelial activation by various mechanisms. The influence of PTX on the plasma levels of soluble adhesion molecules in critically ill patients undergoing continuous veno-venous hemofiltration (CVVH) was studied. DESIGN: Prospective, randomized, blinded study. SETTING: Clinical investigation in the surgical intensive care unit of a university hospital. PATIENTS AND PARTICIPANTS: Fourteen consecutive patients suffering from acute renal failure (ARF) with postoperative complications who received continuous pentoxifylline (CVVH-PTX) i.v. were compared with 14 patients with ARF who did not receive PTX (CVVH control group). INTERVENTIONS: Pump-driven CVVH was carried out with a blood flow ranging from 120 to 150 ml/min. All patients received fentanyl and midazolam continuously and were on mechanical ventilation. PTX (300 mg) was given as a loading dose, followed by continuous infusion of 1.2 mg/kg per h for the next 5 days. MEASUREMENTS AND RESULTS: From arterial blood samples, plasma levels of soluble adhesion molecules (endothelial leukocyte adhesion molecules [sELAM-1], and intercellular adhesion molecule-1 [sICAM-1], vascular cell adhesion molecule-1 [sVCAM-1], and P-selectin granule membrane protein [sGMP-140] were measured using enzyme-linked immuno-sorbent assays (ELISA). Measurements were carried out before the start of CVVH to establish baseline values and continued during the next 5 days. MAIN RESULTS: Eleven of the CVVH-PTX patients and 8 of the CVVH control patients survived during the investigation period. In the CVVH-PTX patients 2.4 +/- 0.3 g/day of PTX was given. At baseline, plasma levels of sELAM-1, sICAM-1, and sVCAM-1 were markedly higher than normal in both groups. In the CVVH control patients, all measured soluble adhesion molecules increased further during the study period (sELAM-1 from 90 +/- 22 to 134 +/- 30 ng/ml; sICAM-1 from 958 +/- 173 to 1460 +/- 209 ng/ml; sVCAM-1 from 1100 +/- 188 to 1804 ng/ml; sGM-140 from 499 +/- 102 to 688 +/- 121 ng/ml) (p < 0.05), whereas in the PTX-treated CVVH patients, plasma levels of all soluble adhesion molecules remained almost unchanged. The PaO2/FIO2 increased in the PTX-treated patients (from 209 +/- 67 to 282 +/- 58 mmHg) and remained almost unchanged in the CVVH control patients. CONCLUSION: Leukocyte/endothelial interactions play an important role in the inflammatory process. Circulating adhesion molecules may serve as markers of the extent of inflammation. Continuous i.v. administration of PTX was successful in blunting the increase of soluble adhesion molecules in critically ill patients undergoing CVVH. Whether these effects result from improved circulation at the microcirculatory level or from (direct or indirect) beneficial effects on endothelial cells warrants further controlled studies.

Acute Kidney Injury↗
PubMed1996

Intraoperative salvage in patients undergoing elective abdominal aortic aneurysm repair: an analysis of cost and benefit.

PURPOSE: Although autologous blood procurement has become a standard of care in elective surgery, recent studies have questioned its cost-effectiveness. We therefore reviewed our 3-year experience with intraoperative cell salvage in patients who underwent elective abdominal aortic aneurysm repair. METHODS: A 3-year retrospective chart review of elective abdominal aortic aneurysm (infrarenal and suprarenal) repair was performed. Transthoracic repairs were excluded. RESULTS: Estimated blood lost was 1748 +/- 1236 ml, or 35% of baseline blood volume (5012 +/- 689 ml). Overall, 164 (89%) received red blood cell (RBC) transfusions (3.5 +/- 2.0 U/patient). The cost per patient for cell salvage was $315 +/- $97, representing 31% of all RBC costs and 24% of total blood component costs. Mean salvage volume infused was 578 +/- 600 ml; at a mean hematocrit level of 55.7% the RBC volume infused from salvage during surgery was 313 +/- 328 ml (representing 27% of total RBC volume lost during the hospital stay). This mean RBC volume salvaged represented the equivalent of 1.6 blood bank RBC units. The mean blood bank costs saved by using cell salvage was $248, or 79% of the $315 actually spent for salvage. We found no decrease in percentage of patients undergoing transfusion until salvage volumes that were infused exceeded 750 ml, or the equivalent of two blood bank units; all of these patients who benefitted had estimated blood lost > or = 1000 ml. CONCLUSIONS: We conclude that use of intraoperative cell salvage was most beneficial for patients who had estimated blood loss greater than or equal to 1000 ml and cell salvage volumes infused greater than or equal to 750 ml. Patients who are estimated to lose less than 1000 ml receive little benefit yet incur substantial costs from intraoperative cell salvage.

Aged↗
PubMed1996

Agrococcus jenensis gen. nov., sp. nov., a new genus of actinomycetes with diaminobutyric acid in the cell wall.

Two strains of a new gram-positive coryneform bacterium isolated from soil and from a sandstone surface are described. Strain 2002-39/1T (T = type strain) is a coccoid, nonmotile, non-acid-fast, microaerophilic organism. The menaquinones of this strain are MK-12 and MK-11, and the main components of the whole-cell sugars are glucose and rhamnose. No mycolic acids are present. The G+C content of the DNA is 74 mol%. Comparative 16S ribosomal DNA studies and a cell wall analysis revealed that this strain represents a new genus belonging to the group of actinomycetes that have diaminobutyric acid in their peptidoglycans. The second strain, strain ST54, which was isolated from a sandstone surface, had the same characteristic features as strain 2002-39/1T. The name Agrococcus jenensis gen. nov., sp. nov., is proposed for these organisms. The type strain is strain 2002-39/1, which has been deposited in the German Collection of Microorganisms and Cell Cultures as strain DSM 9580.

Actinomycetales↗
PubMed1996

The influence of volume therapy and pentoxifylline infusion on circulating adhesion molecules in trauma patients.

Adhesion molecules appear to play a pivotal role in tissue damage secondary to the inflammatory process. Besides neutrophil- and endothelial-bound adhesion molecules, soluble forms have been detected in the circulating blood. They seem to be good markers of endothelial damage, but they may also have other biological functions. Plasma concentrations of soluble adhesion molecules (endothelial leucocyte adhesion molecules (sELAM-1), intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), and granule membrane protein 140 (sGMP-140) were serially measured over 5 days by enzyme-linked immunosorbent assays (ELISA) in 45 consecutive trauma patients. These received, by random allocation, only either hydroxyethylstarch solution 10% (mean molecular weight 200,000 daltons) (n = 15) or human albumin 20% (n = 15) for volume therapy. Another 15 patients without defined volume therapy received pentoxifylline continuously (1.2 mg.kg-1.h-1). Measurements were carried out on the day of admission to the intensive care unit (baseline) and during the next 5 days. At baseline, plasma concentrations of all adhesion molecules were similar in all groups. In the hydroxyethyl starch group, sELAM-1 and sICAM-1 concentrations decreased significantly (p < 0.05) reaching normal values during the study period whereas the mean (SD) values increased in the pentoxifylline group (sELAM-1: 71.1 (16.7) to 91.6 (17.8) ng.ml-1) and the albumin group (sICAM-1: 400 (81) to 749 (101) ng.ml-1) (p < 0.05). sVCAM-1 increased outside the normal range only in the human albumin group (to 760 +/- 69 ng.ml-1) (p < 0.05). sGMP-140 plasma concentration increased only in those receiving albumin (432 (85) to 550 (93) ng.ml-1) and this was significantly different to the other groups (p < 0.05). None of the other haemodynamic or laboratory factors could be correlated with plasma concentrations of the adhesion molecules. We conclude that volume therapy with hydroxyethyl starch resulted in a decrease in circulating adhesion molecules in our trauma patients. In contrast, volume therapy with albumin did not exert this effect. Continuous infusion of pentoxifylline did not have a beneficial modulating action on circulating adhesion molecules.

Adult↗
PubMed1996

Recruitment of purinergically stimulated Cl- channels from granule membrane to plasma membrane.

HT29-Cl.16E and HT29-Cl.19A are two different subcloned cell lines derived from the human adenocarcinoma cell line HT-29. They are similar in their ability to grow and differentiate to polarized epithelial cells but differ in that HT29-Cl.16E is goblet cell-like with many mucin granules, whereas HT29-Cl.19A lacks mucin granules. Extracellular ATP stimulates Cl- secretion in both cell lines through luminal purinergic P20 receptors and, in HT29-Cl.16E, also mucin secretion release. To evaluate whether fusion of mucin granules is associated with an increase in Cl- conductance of the plasma membrane, the effects of two fusion inhibitors on luminal Cl- conductance were measured. Blockage of actin depolymerization with phalloidin (1 microM) inhibited purinergically stimulated but not adenosine 3',5'-cyclic monophosphate (cAMP)-stimulated luminal Cl- efflux by 50% in HT29-Cl.16E. The same treatment was without effect in HT29-Cl.19A. The fungal metabolite wortmannin, which is an inhibitor of regulated exocytosis in leukocytes, at 100 nM inhibited Cl- secretion by 70% in HT29-Cl.16E. This inhibition was not a direct effect on purinergically stimulated Cl- channels because wortmannin concentrations of up to 1 microM did not affect the secretory response in HT29-Cl.19A. The wortmannin inhibition of Cl- secretion is associated with an inhibition of granule fusion as judged by electron microscopy. The differential inhibition of Cl- secretion in the related HT-29 clones that differ with respect to the presence of mucin granules indicates that 1) the granule fusion inhibitors, phalloidin and wortmannin, have no direct inhibitory effects on purinergically and cAMP-activated Cl- channels, 2) a major portion of purinergically but not cAMP-activated Cl- channels is associated with granule fusion in HT29-Cl.16E, and 3) the signaling pathways for Cl- secretion and granule fusion are not completely identical.

Actins↗
PubMed1996

The effect of prolonged pneumoperitoneum on renal function in an animal model.

BACKGROUND: Prolonged, increased intra-abdominal pressure (IAP) during laparoscopic surgery has been associated with oliguria and anuria. STUDY DESIGN: The objective of this study was to evaluate the effects of various levels of IAP on renal function. Ten groups of three adult female farm pigs were given a general anesthetic, followed by establishment of an IAP of 0, 5, 10, 15, or 20 mm Hg with CO2, 20 mm Hg with argon gas, abdominal wall lift device, renal vein occlusion (RVO), 15 mm Hg with CO2 plus dopamine administration at 2 microgram/kg/minute, or 20 mm Hg retroperitoneal CO2 insufflation. The following studies were recorded: baseline central venous pressure (CVP), pulmonary wedge pressure (PWP), cardiac output (CO), renal vein flow (RVF), renal artery pressure (RAP), selective urine output (UO), urinary osmolarity, and creatinine clearance; the parameters were repeated every 30 minutes for the four hours of the IAP study and two hours after release of the IAP. RESULTS: The results were analyzed within two main IAP groups: less than 15 mm Hg and greater than or equal to 15 mm Hg. There was no clinically significant variation in the CVP, PWP, and RAP. The CO decreased slightly and this was more significant in the greater than or equal to 15 mm Hg group. The RVF and UO decreased concomitantly and significantly in the greater than or equal to 15 mm Hg group. Even after two hours of desufflation, the RVF did not return to baseline, although the UO improved. Creatinine clearance decreased significantly in the greater than or equal to 15 mm Hg group. The RVO group exhibited similar changes in the study parameters as those seen in the greater than or equal to 15 mm Hg group, although the RVF did not improve on release of the renal vein in the RVO group. Changes were the same with an argon or CO2 IAP of 20 mm Hg. The abdominal wall lift device had an associated decrease in RVF at 15 KG force but no alteration in UO. Retroperitoneal insufflation resulted in the same decrease in RVF and UO as seen with the same IAP. Dopamine did not afford a protective effect on UO during an IAP of 15 mm Hg. CONCLUSIONS: The decreased UO during prolonged IAP greater than or equal to 15 mm Hg in the animal model is associated with a corresponding decrease in RVF, but does not appear to be associated with any permanent renal derangement nor any transient histologic changes.

Animals↗