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Biomedical subjects

R Thomas

Publications and source records attributed to R Thomas.

At least 19 recordsLinked to original sources
PubMed1992

Rheumatoid synovium is enriched in CD45RBdim mature memory T cells that are potent helpers for B cell differentiation.

OBJECTIVE: To delineate the phenotype and function of synovial T cells in rheumatoid arthritis (RA). METHODS: T cells from normal subjects or from RA peripheral blood (PB), synovial fluid (SF), or synovial tissue (ST) were analyzed phenotypically and functionally. RESULTS: RA SF and ST T cells were found to be markedly enriched in CD45RAdim, CD45RO+, CD45RBdim mature memory cells, whereas in the PB, CD45RAbright naive T cells were more frequent than CD45RO+ memory T cells, and only a minority were CD45RBdim. SF and ST T cells proliferated less well and produced less interleukin-2 in response to mitogenic stimuli than did PB T cells. However, synovial T cells effectively promoted the production of Ig from normal B cells. Moreover, PB and synovial T cells differed in their capacity to down-regulate immunoglobulin production. Anti-CD3-stimulated PB T cells suppressed Ig production unless their proliferation was prevented with mitomycin C. In contrast, synovial T cells were potent helpers of B cell Ig production regardless of antecedent treatment with mitomycin C. To examine the relationship between the CD45RBdim phenotype and B cell help, CD45RBdim T cells were sorted from PB. As opposed to the findings with synovial T cells, suppression by control PB CD45RBdim T cells was observed, but only when large numbers were employed. B cell Ig production was enhanced after treatment of PB CD45RBdim T cells with mitomycin C. In contrast, healthy control sorted CD45RBbright or sorted CD4+, CD45RO+, CD45RBbright T cells did not support Ig secretion. After treatment with mitomycin C, both of these populations were more effective helpers of Ig production. CONCLUSION: RA synovium is enriched in differentiated CD45RBdim memory T cells with potent helper activity and diminished capacity to down-regulate B cells, strongly implying an active role for these cells in the production of Ig in the synovium, and thus in the propagation of disease.

Adult↗
PubMed1992

Hemodynamic effects of oral amiodarone on left ventricular function before and after global ischemia.

We evaluated the hemodynamic effects of amiodarone on left ventricular (LV) function after global ischemia. Amiodarone was administered orally at 15 mg/kg/day for an average of 28 days to a group of 10 dogs. The concentration of amiodarone in serum and LV myocardium was 0.40 +/- 0.24 micrograms/ml and 44 +/- 27.0 micrograms/g, respectively. This experimental group and a control group of 10 dogs each underwent 120 min of aortic cross-clamping with cold crystalloid cardioplegia resulting in an average myocardial temperature of 15 degrees C. LV function measurements by pulse-transit sonomicrometry and Millar solid-state micromanometers were processed by a minicomputer. Compared to the nontreated control group, oral amiodarone for 28 days produced depression of LV contractility which was reflected by lower slope of the end-systolic pressure-volume relation (Evmax), percentage shortening of segment length, left ventricular pressure-segment length loop area, and slope of the end-systolic pressure-segment length relation (Esmax). After ischemia, percentage recovery of LV global function (Evmax and mean velocity of circumferential fiber shortening) and regional function (Esmax) was significantly better in the amiodarone group than in the control group. We conclude that oral amiodarone for 28 days results in a depression of LV contractility but the combination of amiodarone and ischemia does not act synergistically to further depress postischemic LV function.

Administration, Oral↗
PubMed1992

How to improve the quality of patient care and still save money in the radiology department.

1, A pediatric radiology department at an institution such as Minneapolis Children's Medical Center is a true microcosm of the gigantic radiology department of a general hospital. Our positive experiences with IMACS discussed above should be even more profound and profitable for the larger medical institutions. 2, IMACS did improve service and communications among radiologists, referring clinicians and the hospital staff. Both the old and new images needed for review and comparison are presently available for the clinicians on the nursing stations as soon as the current studies have been completed. 3, IMACS allowed us to reduce the number of films lost, misplaced or misfiled and reduced the interpretation delays by keeping all the films in the radiology department. This has resulted in improvement in the overall productivity of the radiology staff and the referring clinicians. 4, The cost of IMACS was paid for through additional revenue capture, increased productivity and a decrease in the expenses in the radiology department in less than one year. These benefits should continue for several more years without the need for any additional expenses. 5, Despite these initial successes, there are several issues which must be addressed before total computerization of the radiology services and a "filmless" radiology department can be created. A. The speed of an available workstation is totally inadequate for the day to day clinical use.(ABSTRACT TRUNCATED AT 250 WORDS)

Cost Control↗
PubMed1992

Effect of extracorporeal shock wave lithotripsy on renal function and body height in pediatric patients.

Although extracorporeal shock wave lithotripsy (ESWL) is the preferred modality for treatment of most renal and upper ureteral calculi in adults, little is known about its effect on the pediatric population. We carefully followed 12 children 2.2 to 15.3 years old (mean age 9.4) treated with the Dornier HM3 lithotriptor. Effective renal plasma flow was obtained by quantitative 131iodine hippurate scan immediately preceding ESWL and at followup (range 74 to 238 weeks, mean 149). The treated kidney received an average of 1,702 shocks (range 1,000 to 2,200). Mean effective renal plasma flow increased in the treated kidney from 185 cc per minute before ESWL to 217 at followup (p = 0.016) and in the untreated kidney from 191 to 224 (p = 0.0013). Total effective renal plasma flow increased from 376 cc per minute before ESWL to 440 at followup (p = 0.0019). In the treated kidney mean and total effective renal plasma flow increased by 31 (expected 32) and 64 (expected 68) cc per minute, respectively, while in the nontreated kidney mean effective renal plasma flow increased by 33 (expected 36) cc per minute. None of the observed changes in effective renal plasma flow was significantly different from the expected changes using the paired t test at the 95% level. In addition, change in body height was evaluated using standard deviation scores. Mean body height (standard deviation) before ESWL was -0.39 (range -3.2 to 2.0) and at last followup it was -0.26 (range -2.6 to 2.4), which is not statistically significant (p = 0.37). Although these patients continue to be followed and caution is advised, this long-term study indicates that ESWL within the range of shocks delivered to this cohort does not statistically affect linear growth (body height) or renal function in the pediatric population.

Adolescent↗
PubMed1992

Diagnosis of systemic histoplasmosis in patients with AIDS.

To compare various laboratory methods for diagnosis of systemic histoplasmosis, we retrospectively reviewed the charts of 165 patients with AIDS (acquired immunodeficiency syndrome). In eight of those patients, systemic histoplasmosis was confirmed by laboratory techniques. The laboratory methods used were histomorphology and microbiology. Tissues and fluids used for fungal cultures and histochemical stains included blood, bone marrow, lung, skin, pleura, esophagus and colon biopsy specimens, sputum, cerebrospinal fluid, bronchial washing/brushing, and pleural and peritoneal fluids. Results were positive in 83% of blood cultures and 71% of bone marrow cultures, making these tissues the best sources of Histoplasma organisms for microbiologic study. Similarly, Histoplasma sp could be demonstrated by fungal stains in 75% of bone marrow biopsy specimens as the main source for morphologic documentation of systemic histoplasmosis. The other tissues and fluids were only occasionally positive either microbiologically or morphologically. There was cross-positivity between morphologic and microbiologic methods in 80% of confirmed cases, making both methods equally reliable. However, the results were obtained within 48 hours by histomorphology, allowing prompt initiation of antifungal therapy. Although more specific results were produced by microbiologic methods, it took 18 to 35 days to grow the organism.

AIDS-Related Opportunistic Infections↗
PubMed1992

An investigation of the pharmacokinetics of topical terbinafine (Lamisil) 1% cream.

Twenty human volunteers were entered into a study to investigate the pharmacokinetics of terbinafine 1% cream. Subjects were randomized to receive terbinafine 1% cream applied to the back on 1 day, or on 3, 5 or 7 consecutive days. Up to five sequential skin surface biopsies were taken at a site on the upper back at various time-points both during treatment, and following cessation of treatment. Terbinafine levels in these biopsies were analysed using HPLC. The study showed that increasing the number of applications from one to seven did not significantly increase the peak concentration (Cmax) in the stratum corneum. It did, however, increase the total amount of terbinafine found in the stratum corneum, resulting in terbinafine being detected for longer periods after cessation of therapy. Treatment for 7 days resulted in terbinafine still being detectable 7 days after cessation of therapy, when the terbinafine concentration was significantly higher than the known cidal concentrations for the common causative organisms of superficial dermatomycoses. This study indicates a significant potential for short-duration treatment with terbinafine (Lamisil) 1% cream in superficial dermatomycoses.

Administration, Topical↗
PubMed1992

Diagnosis and treatment in a case of juvenile subacute necrotizing encephalopathy Leigh without cytochrome c oxidase deficiency.

Subacute necrotizing encephalopathy (Leigh syndrome) is characterized by lactacidosis, seizures, ataxia, multiple cerebral hypervascularized lesions and mitochondrial oxidation defects. This is a report on a 21-year-old patient with proven Leigh syndrome, mild central and provokable peripheral lactacidosis, an extra-erythrocyte complex II defect, functionally reduced myokinase adenylate deaminase activity, but no ultrastructural mitochondrial changes. Determination of lactate, pyruvate and ammonia under ischemic conditions plus a pyruvate loading test were particularly useful. Oral flunarizine (Sibelium 30 mg/d) proved to be therapeutically effective.

Biopsy↗
PubMed1991

Pyomyositis complicating the acquired immunodeficiency syndrome. A report of two cases with coexistent neutropenia.

OBJECTIVE: To identify some factors contributing to the development of pyomyositis in patients with the acquired immunodeficiency syndrome (AIDS) by a report of two cases and a review of the literature. CLINICAL FEATURES: A 36-year-old man with AIDS presented with tenderness of the left adductor longus muscle; a 28-year-old man with AIDS presented with fever and left leg pain. Both men had a history of severe neutropenia induced by drug treatment and opportunistic infections requiring treatment in hospital. The pyomyositis was defined by a gallium-67 scan (and, in one case, by a computed tomography scan). In one case Staphylococcus aureus was cultured from blood; in the other it was cultured from pus from the pyomyositic abscess. INTERVENTIONS: Both patients had their abscesses drained. The first patient was treated with flucloxacillin (2 g every four hours, given intravenously) and rifampicin (450 mg by mouth each day). The second patient was treated with flucloxacillin (2 g every four hours, given intravenously) and ticarcillin (3 g every six hours, given intravenously). OUTCOME: After their symptoms abated, both patients were discharged from hospital, taking flucloxacillin by mouth as ongoing treatment. CONCLUSIONS: Staphylococcal infections are increasingly common in neutropenic patients. Neutropenia is likely to have contributed to the development of pyomyositis in these patients.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Acute nondilated anuric obstructive nephropathy on echography: difficult diagnosis in the intensive care unit.

Renal echography (RE) is a well recognized, accurate, non-invasive imaging procedure for detecting urinary tract (UT) obstruction in Intensive Care Unit (ICU) patients: a dilated collecting system is usually present but a few cases of nondilated obstructive nephropathy have been previously described. We report the clinical, biological, imaging procedure data and outcome of 6 additional cases of anuric obstructive nephropathy without dilatation on one or more RE. All patients had previous and/or actual history suggestive of UT obstruction. Retrograde ureteropyelography (RUP) was performed in all of them: it provided the diagnosis of obstruction in 4 and was immediately followed by dramatic improvement of renal function in all, including the 2 patients with septic shock from proven or suspected UT origin. The cause of obstruction was a neoplastic retroperitoneal process in 4. We conclude that anuric nondilated obstructive renal failure is not uncommon and should be considered in anuric patients when UT obstruction is likely to occur. The sole visualization of a non-dilated collecting system on RE should lead to repeat RE, especially in hypovolemic anuric patients. RUP provided immediate diagnostic and therapeutic benefits in comparison with other imaging procedures in our series.

Aged↗
PubMed1991

Growth of tracheal anastomoses: advantage of absorbable interrupted sutures.

Growth of the trachea after complete transection and anastomosis was studied in four groups of 1-month-old New Zealand white rabbits. The trachea was transected at the fifth cartilaginous ring and then anastomosed with continuous 6-0 polypropylene (Prolene) (group 1), interrupted 6-0 polypropylene (group 2), continuous 6-0 polydioxanone (PDS) (group 3), or interrupted 6-0 PDS (group 4). The animals were followed up for 90 to 103 days (mean follow-up, 95 days). At the time the animals were killed, body weight had increased 125% (1.2 to 2.7 +/- 0.18 kg). Growth of the trachea was assessed at the time of death. Results from this study suggest that growth of a tracheal anastomosis is retarded in a growing animal model. The degree of resultant stenosis was significantly less when an absorbable suture material (PDS) and an interrupted suturing technique were used.

Anastomosis, Surgical↗