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Biomedical subjects

R Thomas

Publications and source records attributed to R Thomas.

At least 433 records · Page 24Linked to original sources
PubMed1993

Isolation and characterization of human peripheral blood dendritic cells.

Dendritic cells (DC) are potent APC that can be purified from cultured peripheral blood non-T cells. Because no specific cell surface marker has been found, the lineage of DC remains obscure. The purpose of these studies was to determine the circulating blood cells that could give rise to functional human DC. DC were enriched when purified by standard techniques from non-T cells that were treated with L-leucyl-L-leucine methyl ester, known to be toxic to monocytes and cytolytic cells. To determine whether monocytes or B cells could give rise to DC, fresh non-T cells were sorted into CD14+ monocytes, CD19+ B cells, and CD14- and CD19- cells. Although there was some enrichment for APC function by cultured nonadherent CD14- or CD19- cells, a marked enrichment for cells with dendritic morphology and potent APC function was found in the population that was sorted by the absence of expression of CD14, CD19, CD3, and CD16. More than 90% of the CD14-CD19-CD16-CD3- sorted cells, and of control DC, expressed the myeloid markers CD13 and CD33. Therefore, fresh non-T cells were sorted based on the expression of these myeloid markers. In comparison with CD33-CD14- B cells, some of the CD33+ cells expressed CD14 dimly. However, they were easily distinguished from monocytes, which intensely expressed CD14. CD33+CD14dim cells developed dendritic processes and were more potent APC than control DC, CD33+CD14+, or CD33-CD14- cells. Although freshly isolated CD33+CD14dim DC expressed a number of cell surface molecules also expressed by CD14+ monocytes, they demonstrated lower levels of lysosomal enzymes and a lack of FcR-mediated phagocytosis in comparison with monocytes. Differentiation of morphology and phenotype of CD33+CD14dim cells occurred within 6 to 36 h in culture. However, the CD33+CD14dim cells could effectively function as APC without prolonged preincubation to develop dendritic morphology. These data indicate that human blood DC arise from precursors that express the myeloid lineage markers CD13 and CD33, but are functionally distinct from classic CD14+ monocytes.

Antigen-Presenting Cells↗
PubMed1993

[Clinical and etiological diagnosis of septic states].

The sepsis concept implies a clinical suspicion of infection and a diagnosis of host's response to this infection. In increasing order of severity are simple sepsis, severe sepsis and septic shock. The semeiology of sepsis consists of systemic signs and elements of information on various visceral dysfunctions. The aetiological investigation is based on the patient's diathesis, on whether the infection is hospital- or community-acquired, on the severity of the sepsis and on simple clinical and paraclinical data. Gram-positive infections are usually caused by pneumococci and staphylococci, and Gram-negative infections by meningococci and enterobacteriaceae. Hospital-acquired infections are remarkable for their frequency, their severity and the diagnostic problems they raise due to patients' colonization and multiple portals of entry. With the exception of some microbiological situations (parasites, fungi, viruses), the main problems raised by non-bacterial sepsis relate to occult sepsis and systemic inflammatory responses to some acute pathologies, such as burns, pancreatitis or multiple injuries. To conclude, redefining the nosology of severe infections to include the fundamental concept of host's response should result in a better evaluation of the infection, its consequences and the treatment of both.

Humans↗
PubMed1993

Reduction of leukocyte and interleukin-1 beta concentrations in the synovial fluid of rheumatoid arthritis patients treated with methotrexate.

OBJECTIVE: To examine the effect of methotrexate (MTX) on the numbers of leukocytes in the peripheral blood (PB) and synovial fluid (SF) of patients with active rheumatoid arthritis (RA). METHODS: Twelve patients were treated with MTX; 5 patients not taking MTX served as controls. Samples of PB and SF were collected at 0, 1, 4, and 8 weeks of the study. Disease activity was scored, and total leukocytes, neutrophils, lymphocytes, and CD4+, CD8+, DR+, and CD25+ lymphocyte subsets were analyzed in PB and SF. Interleukin-1 beta (IL-1 beta) concentrations in SF were determined. RESULTS: Patients treated with MTX showed significant clinical improvement. No change in PB leukocytes or lymphocyte subsets was observed in either patient group over the 8-week study period. In contrast, the number of leukocytes, the number and proportion of neutrophils, and the concentration of IL-1 beta in the SF of patients treated with MTX were reduced. In addition, in MTX-treated patients, there was an appreciable decrease in SF CD8+ lymphocytes, but not CD4+, DR+, or CD25+ lymphocytes. CONCLUSION: These findings suggest that in RA, MTX acts, at least in part, by reducing the migration of leukocytes into the inflamed synovium. Local reduction of IL-1 beta secretion may contribute to this effect.

Aged↗
PubMed1993

Symmetry of cerebral blood flow and cognitive responses to hypoglycaemia in humans.

A low blood glucose level is associated with impairment of higher cerebral function and an increase in cerebral blood flow. This study examined whether there are differences in the physiological responses to hypoglycaemia between the cerebral hemispheres. Eight healthy men participated in two hyperinsulinaemic glucose clamp studies: after 60 min at 4.5 mmol/l, blood glucose was either lowered to 2.0 mmol/l and "clamped" there for 60 min (hypoglycaemia) or continuously maintained at 4.5 mmol/l (euglycaemia). Cardiac output, middle cerebral artery velocity (transcranial Doppler) and cerebral blood flow (133-xenon inhalation) were measured during the studies. Neuropsychological tests were used to determine whether hypoglycaemia caused differential impairment of hemispheric cognitive function. Hypoglycaemia was associated with symmetrical impairment of cognitive function in both cerebral hemispheres and a rise in cardiac output (from 5.5 [0.2] to 8.7 [0.2] l.min-1, p < 0.0001, mean [standard error]), middle cerebral artery velocity (from 55 [2.6] to 64 [2.8] cm.s-1, p < 0.002), and global cerebral blood flow (from 56 [2.6] to 69 [2.9] ml.100 g-1.min-1, p < 0.005 compared to pre-insulin values). There were no differences in the blood flow response during hypoglycaemia between hemispheres and the increase in blood flow did not correlate with either the change in cardiac output or rise in plasma catecholamine levels. After 120 min of hyperinsulinaemic, euglycaemia, global cerebral blood flow rose significantly above baseline (from 58 [2.4] to 63 [2.2] ml.100 g-1.min-1, p < 0.05). In conclusion, using the techniques described, the physiological and cognitive responses of each cerebral hemisphere to hypoglycaemia were symmetrical.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Penile agenesis associated with urethral and bilateral renal agenesis.

Penile agenesis is a rare anomaly, with an estimated incidence of 1 in 30 million. Most cases are compatible with life but require early surgical intervention. This case is unusual in that there was an associated agenesis of the kidneys and urethra leading to fatal oligohydramnios sequence with pulmonary hypoplasia.

Abnormalities, Multiple↗
PubMed1993

A typology of care episodes experienced by people with schizophrenia in an English town.

The paper presents an analysis of the psychiatric care histories of people diagnosed with schizophrenia which is set within the policy context of the deinstitutionalisation debate. The durations of successive terms of in-patient and community care were drawn from the records of the Salford Psychiatric Case Register and related to the age, gender and social isolation of each patient. Strong age-sex interactions are revealed by the tendencies for young male patients to exhibit rapid hospital readmission and discharge rates and elderly female patients to experience long terms of in-patient care. The role of social isolation in relation to these care durations turns out to be more restricted.

Adult↗
PubMed1993

Extracorporeal shock wave lithotripsy in morbidly obese patients.

Management of urolithiasis in morbidly obese patients is usually associated with higher morbidity and mortality compared to nonobese patients. In morbidly obese patients, since the kidney and stone are at a considerable distance from the skin (compared to nonobese patients), difficulty may be encountered in positioning the patient so that the stone is situated at the F2 focal point of the lithotriptor. Using various aids, such as the extended shock pathway and abdominal compression, we treated 81 patients weighing more than 300 pounds using the Medstone STS tubless second generation lithotriptor. The stone-free rate at 3 months or longer was 68%, with another 10% having asymptomatic fragments of 4 mm. or less in diameter. Thus, a clinical stone-free rate of 78% was achieved. The retreatment rate was 11% and the post-lithotripsy secondary procedures rate was 3%. Since these results are comparable to those obtained when treating patients less than 300 pounds, extracorporeal shock wave lithotripsy can be used successfully to treat urolithiasis in morbidly obese patients.

Humans↗
PubMed1993

Cell wall deficient bacteria as a cause of idiopathic hematuria.

Idiopathic hematuria in the absence of bacteriuria is a medical challenge. Routine cultures of catheterized bladder and endoscopically obtained ureteral urine specimens from a 22-year-old woman with a 6-week history of hematuria showed no growth after 24 to 48 hours of incubation. However, bacterial variants were grown on enriched media. Colonies were typical cell wall deficient/defective bacteria. Phase and electron microscopy of cystoscopic urine specimens obtained by retrograde ureteral catheterization as well as phase microscopy of the cultures revealed the classic morphology of these organisms. When the variant cultures were subcultured the organisms reverted to their related walled forms, that is Streptococcus agalactiae and Staphylococcus haemolyticus. Because the colonies of these organisms showed various patterns of biochemical reactivity, each phenotype was tested against 15 antimicrobials. Collectively, all biotypes had a common susceptibility to only nitrofurantoin. The patient was treated with nitrofurantoin for 6 weeks. Four days after initiation of therapy she had complete remission of hematuria. During the next 3 years she remained well and free of hematuria.

Adult↗
PubMed1993

Direct percutaneous pouch cystostomy with endoscopic lithotripsy for calculus in a continent urinary reservoir.

Continent urinary reservoirs are an accepted mode of urinary diversion in appropriate patients. Such procedures are associated with long-term complications. A patient who underwent a continent urinary diversion (modified Indiana pouch) 4 years ago for a neurogenic bladder presented with a large irregular calculus in the pouch. Endoscopic attempts to remove the calculus through the stoma were unsuccessful and extracorporeal shock wave lithotripsy failed to fragment the pouch calculus. Finally, an endoscopic approach through a direct percutaneous pouch cystostomy, and use of ultrasonic and electrohydraulic probes resulted in successful fragmentation and removal of the calculus.

Adult↗
PubMed1993

Safety and efficacy of pediatric ureteroscopy for management of calculous disease.

Ureteral calculi, although relatively uncommon in children in the United States, have traditionally been managed with open surgical removal. Innovations in managing ureteral stones in the adult population have not readily been used to manage such problems in children due to unknown effects on the ureterovesical junction and to the unavailability of smaller caliber ureteroscopes. We report on the technique and long-term (average 26 months, range 3 to 56) safety following 18 successful ureteroscopic procedures for stone removal in 16 patients 16 months to 15 years old. All children were rendered stone-free. Followup quantitative renal scans and excretory urography showed adequate renal growth. No incidence of vesicoureteral reflux occurred in 9 of the 14 patients (64%) available for followup who underwent postoperative cystograms. These results suggest that judicious use of smaller caliber instruments, improved ancillary equipment and experience in such procedures make ureteroscopy a safe procedure for management of ureteral calculi in children.

Adolescent↗
PubMed1993

An innovative approach to management of lower third ureteral calculi.

A total of 130 patients with symptomatic lower third ureteral calculi underwent 136 treatments by 43 accredited urologists. These treatments were performed at a fixed lithotripsy site and 16 mobile sites using the Medstone lithotriptor from December 1990 through January 1992. The average stone size was 8.16 x 5.14 mm. A total of 126 patients underwent a single treatment and 4 underwent multiple treatment sessions. Of the 126 patients undergoing monotherapy 10 (8%) were lost to followup, while 101 of the remaining 116 evaluable patients (87%) were stone-free with a single treatment. The 15 patients in this subgroup who were considered failures and the 4 patients who underwent multiple treatments had overall larger stone sizes. The preoperative stent placement rate was only 32%. The treatments were well tolerated by the patients. Our report confirms a high efficacy rate with the second generation bathless lithotriptor for management of lower third ureteral calculi. The importance of a stable and qualified technical team cannot be overemphasized.

Equipment Design↗
PubMed1993

Sensorineural hearing loss in neurobrucellosis.

A case of neurobrucellosis presenting to the otologist with sensorineural hearing loss (SNHL) as the predominant clinical feature is reported. The diagnostic features and treatment options are discussed and the need for prolonged combination treatment to prevent relapse and further deterioration of hearing stressed. SNHL in neurobrucellosis has hitherto been reported principally in neurology literature as something of an incidental finding and so escapes the attention of otologists. It is hoped that this report will alert otologists in areas where brucellosis is endemic to the need to include tests for brucellosis in the routine diagnostic screening for SNHL. Practitioners in other locations should also consider this possibility when dealing with patients who have visited or lived in endemic regions.

Adult↗
PubMed1993

Indwelling ureteral stents: impact of material and shape on patient comfort.

Indwelling ureteral stents are essential in urology today. No ideal stent has been designed. The principal sources of discomfort are a long intravesical segment, inefficient drainage, displacement, and stiffness. Discomfort may be a small price to pay for the overall benefit to the patient.

Biocompatible Materials↗
PubMed1993

Absence of long-term gonadotoxicity in primates receiving extracorporeal shock wave application.

Extracorporeal shock wave lithotripsy (SWL) is becoming popular in the management of lower ureteral calculi; however, the quantity of data on its potential gonadotoxic effects are limited. Eight nonhuman primates had baseline measurements of testicular volume, semen analysis, serum testosterone and FSH assays, and DNA flow cytometric analysis of testicular aspirates. The anesthetized primates were lowered into a Dornier XL-1 lithotripter and at a 20 kV power setting had various numbers of shocks (0, 500, 1500) directed at each testis. Sequential studies were done at 6-week intervals for 9 months. The control group showed no significant change in any measure. Semen analysis, testosterone, and FSH results were variable and without statistically significant differences. There were changes in the DNA histograms, with the tetraploid (4N) group of cells being the most sensitive. All changes caused by SWL application returned to baseline by 9 months. Data from this primate study document no apparent long-term male gonadotoxicity from SWL, but the authors suggest measures to protect the testis during clinical use.

Animals↗
PubMed1993

Echocardiographic volume flow and stenosis severity measures with changing flow rate in aortic stenosis.

The anatomy of degenerative valvular aortic stenosis has been poorly represented in animal models, limiting the evaluation of noninvasive echo-Doppler measures of transvalvular volume flow rate and stenosis severity during progressive disease evolution or under conditions of changing volume flow rates. To study these issues, chronic valvular aortic stenosis, characterized by stiff leaflets without commissural fusion, was created in nine adult mongrel dogs by suturing pericardial covered Teflon-felt pads into the sinuses of Valsalva below the coronary ostia during hypothermic cardiac arrest. In the eight surviving dogs, echo-Doppler examinations were performed weekly for up to 8 wk postoperatively. Simultaneous invasive micromanometer pressure data were collected at 2-wk intervals in all subjects, with simultaneous ascending aortic transit time-volume flow measurement in four subjects. Volume flow rates were altered with saline and dobutamine infusions during invasive studies for comparison of echo-Doppler and invasive pressure gradients, volume flow, and valve areas. Serial echo-Doppler follow-up (39 +/- 11 days) demonstrated that, from baseline to final study, mean transvalvular pressure gradient increased (4 +/- 1 to 38 +/- 7 mmHg, P = 0.001), continuity equation aortic valve area decreased (2.06 +/- 0.18 to 0.54 +/- 0.04 cm2, P < 0.0001), and progressive left ventricular hypertrophy developed (62 +/- 6 to 114 +/- 9 g, P = 0.0003). Echo-Doppler and invasive data correlated well for measures of transvalvular pressure gradients (n = 98, maximum instantaneous gradient r = 0.95, mean gradient r = 0.91), volume flow (n = 75, stroke volume r = 0.86, cardiac output r = 0.86), and valve area (n = 73, r = 0.73) despite acute alterations in volume flow and progressive disease evolution. This chronic canine model, with anatomy and hemodynamics similar to clinical degenerative valvular aortic stenosis, should provide a valuable tool for investigating clinically relevant new measures of stenosis severity with use of invasive or noninvasive techniques.

Analysis of Variance↗