Search PubMed⌕ Search

Biomedical subjects

M Kessler

Publications and source records attributed to M Kessler.

At least 73 records · Page 4Linked to original sources
PubMed1998

Paternity assessment in rhesus macaques (Macaca mulatta): multilocus DNA fingerprinting and PCR marker typing.

Establishing kinship relations in primates using modern molecular genetic techniques has enhanced the ability to scrutinize a number of fundamental biological issues. We screened 51 human short tandem repeats (STRs) for cross-species PCR amplification in rhesus macaques (Macaca mulatta) and identified 11 polymorphic loci with heterozygosity rates of at least 0.6. These markers were used for paternity testing in three social groups (M, R, and S) of rhesus macaques from Cayo Santiago, Puerto Rico. Several consecutive birth cohorts were analyzed in which approximately 200 males were tested for paternity against more than 100 mother/ infant pairs. Despite a combined exclusion rate of more than 99.9% in all three groups, some cases could not be solved unequivocally with the STR markers and additional testing of the MHC-associated DQB1 polymorphism. A final decision became possible through multilocus DNA fingerprinting with one or more of the oligonucleotide probes (GATA)4, (CA)8, and (CAC)5. Paternity assessment by multilocus DNA analysis with probe (CAC)5 alone was found to have limitations in rhesus macaques as regards the number of potential sires which might be involved in a given case. Multilocus DNA fingerprinting requires large amounts of DNA, and the ensuing autoradiographic patterns present difficulties in comparisons across gels and even within the same gel across remote lanes. Computer-assisted image analysis was incapable of eliminating this problem. Therefore, a dual approach to DNA typing has been adopted, using STR markers to reduce the number of potential sires to a level where all remaining candidates can be tested by multilocus DNA fingerprinting on a single gel, preferably in lanes adjacent to the mother/infant pair.

Animals↗
PubMed1998

Dynamic changes in intracapillary hemoglobin oxygenation in human skin following various temperature changes.

To evaluate microvascular regulation in human skin, changes in intracapillary hemoglobin oxygen saturation (HbO2) were studied in human finger skin following an abrupt change in local ambient temperature. In the first series of experiments, we assessed the heterogeneity of HbO2 in the skin by using a 2-D scanning system and a rapid micro-lightguide spectrophotometer at each of two near-normal skin temperatures. The data showed that heterogeneous oxygenation exists in human skin even at near-normal temperatures (although the pattern is different at different skin temperatures). In a second series of experiments, the performance of the microcirculation of the skin was continuously examined in a selected area with initially different oxygenation levels during an abrupt change in local ambient temperature (5, 15, 25, 35, and 45 degrees C). At very low (5 degrees C) or very high (45 degrees C) temperatures, oxygenation in tissues within the low HbO2 area increased greatly, but there was no such change within the high HbO2 area. Our data indicate that different types of capillary supply units exist in human skin (indicated by the initially different oxygenation levels). These different capillary supply units may operate to produce a local redistribution of flow between the various capillary supply units. This effect may be initiated by heat sensors and oxygen sensors when temperature of the skin is varied.

Adult↗
PubMed1998

[Computer-assisted analysis of mammograms in routine clinical diagnosis].

PURPOSE: Computer-aided diagnosis in mammography is a topic many study groups have been concerned with since the first presentation of a system for computer-aided interpretation in 1967. Currently, there is only one system available for clinical use in mammaography, the CAD-System Image Checker (R2 Technology). The purpose of our prospective study was to evaluate whether the integration of the CAD-system into the routine of a radiological breast diagnosis unit is feasible. RESULTS: After the installation of the CAD-system, 300 patients with 1110 mammograms were included for evaluation in the present study. In 54 of these cases histological examination was indicated due to suspect criteria on conventional mammography. In 39 of 54 cases (72.2%) malignancy could be proven histologically. The CAD-system marked 82.1% of the histologically verified carcinomas correctly. 94.3% of all 1797 marks made by the CAD-system indicated normal or benign structures. Routinely performed CAD analysis prolonged patients waiting time by about 15 min because the marks of the CAD system had to be interpreted in addition to the routine diagnostic investigations. CONCLUSION: Our experience with the use of the CAD-system in daily routine showed that CAD analysis can easily be integrated into a preexisting mammography unit. However, the diagnostic benefit is not yet clearly established. Since the rate of false negative marks by the CAD-system Image Checker is still high, the results of CAD analysis must be checked and corrected by an observer well experienced in mammography reading.

Breast Neoplasms↗
PubMed1998

Lymphoproliferative disorders after renal transplantation: role of medical imaging.

Post-transplantation lymphoproliferative disorders (PTLD) are a complication of immunosuppressed transplant recipients, and their incidence is reported to be 20-120 times greater than the rate in the general population. After kidney transplantation, PTLD more likely arise within the renal transplant fossa. Radiological patterns of these forms are presented and discussed, according to a review of the literature, and illustrated by cases from our institution. Ultrasound plays an essential role in the early diagnosis of PTLD by detecting a urinary obstruction associated with adenopathy or an ill-defined mass not previously seen. However, in the case of an inconclusive US examination, CT or MRI should be performed to confirm the presence of a mass. Both techniques are useful in evaluating the extension of the process within the transplantation fossa; MRI seems more accurate and can be used for the follow-up, especially after reduction in immunosuppressive therapy without transplant removal.

Biopsy↗
PubMed1998

[The demonstration of blood flow in focal breast lesions by power-Doppler sonography. A new approach to assessment?].

PURPOSE: Power-Doppler sonography is regarded as a very sensitive method for detecting low-velocity and low-volume blood flows. The purpose of our study was to investigate whether increased vascularity in breast carcinoma can be visualized by power-Doppler sonography and whether new criteria for differentiating benign and malign lesions can be found. METHOD: 315 patients were examined with a 13-MHz high-resolution linear transducer. If a suspicious lesion was found, it was evaluated further by power-Doppler sonography. Compared to normal breast parenchyma (reference structure), a focal increase in blood flow signals was registered using a 3-step grading system with a 4th step for no flow increase. RESULTS: In 97 cases the sonographic findings were correlated with histology (n = 95) or cytology (n = 2). There were 50 benign lesions, 42 cases of invasive and 5 cases of in-situ carcinoma. 73.5% benign lesions showed no or just minimal increases in flow signal. 81% of invasive cancer presented middle- or high-flow increases compared to normal breast parenchyma. The extend of flow increase was linked to tumor size in invasive cancer. In stage T1b to T4, 94.3% of invasive carcinoma presented middle or high flow increases. CONCLUSION: Power-Doppler sonography is able to visualize vascularization in breast tumors. According to first clinical results PD sonography is a promising additional diagnostic tool which seems to offer new criteria for differential diagnosis in breast tumors.

Adult↗
PubMed1998

Treatment of end-stage renal failure after heart transplantation.

BACKGROUND: Five to 10% of heart-transplant recipients develop end-stage renal failure (ESRF). Little is known about the outcome of these patients under renal replacement therapy. METHODS: We conducted a retrospective study in 16 men (mean age 52.8+/-7.4 years at heart transplantation) who developed ESRF 5.3+/-2.1 years later. Results. Haemodialysis (HD) was the first-line treatment (mean Kt/V 1.35+/-0.4). Vascular access was unsuccessful in six patients (37.5%) due to peripheral arteriopathy and they were treated with tunnelled catheters for an average 15 months without bacterial infection. Mean weight was 68.4+/-10 kg at onset of HD and 61.7+/-9 kg one month later. Despite this reduction in extracellular overload, one antihypertensive drug was required in 75% of patients and two drugs in 12.5%. One patient tolerated automated peritoneal dialysis (PD) for 16 months (weekly Kt/V 2.1) despite persistent anuria. Renal transplantation (RT) was contraindicated in eight patients because of aortoiliac arteriopathy (n=5), poor general status (n=2), or ischaemic heart disease (n=1). RT was performed in eight patients with no acute episode of heart or renal graft rejection. There were no serious infectious complications. Three months after RT, mean serum creatinine was 115 micromol/l. One patient developed post-transplant lymphoproliferative disorder 3.5 months after RT and was successfully treated with transplant nephrectomy. Sudden death occurred in two patients 18 and 33 months after RT. Overall patient survival was 100, 78, and 59%, 1, 2 and 3 years after HD onset respectively. Using a time-dependent variable, the Cox model analysis demonstrated that heart-transplant recipients with ESRF have a relative risk of death 3.2 times higher than those without ESRF (95% CI = 1.3-7.8). CONCLUSIONS: HD, PD, and RT can be useful for the treatment of ESRF after heart transplantation. After initiating HD, patient survival is nearly the same as that reported in patients in Europe undergoing HD for other causes. But ESRF seems to reduce life expectancy in heart-transplant recipients.

Adult↗
PubMed1998

In-vitro growth patterns of bone marrow erythroid progenitors from patients with post-renal transplant erythrocytosis.

BACKGROUND: Erythrocytosis is relatively common after renal transplantation and is associated with a higher risk of thromboembolism. Its aetiology is unclear and there is still debate about the most frequently suggested causes. The culture in vitro of erythroid progenitors is regarded as a useful tool for the differential diagnosis of patients with unclear erythrocytosis. We studied the growth in vitro of bone marrow erythroid progenitors from renal transplant patients with erythrocytosis and controls without erythrocytosis. SUBJECTS AND METHODS: Thirteen renal transplant patients with erythrocytosis and 12 normocythaemic renal transplant controls were studied. The clinical characteristics of these patients were evaluated and serum erythropoietin (Epo) and ferritin levels were determined. Bone marrow erythroid progenitors were cultured both with and without the addition of Epo to the medium. RESULTS: Samples from six polycythaemic patients and seven controls did not grow spontaneously in the absence of exogenous Epo. Three cases of post-transplant erythrocytosis and five controls produced CFU-E, but not BFU-E. A few CFU-E and BFU-E grew spontaneously in samples from four polycythaemic patients but not in samples from the controls. Addition of 1 unit per millilitre Epo caused similar increases in the number of colonies in both polycythaemic patients and controls. Of the nine patients eligible for follow-up, all four with spontaneous growth of BFU-E had transient erythrocytosis and four of the five patients with no spontaneous growth or spontaneous growth of CFU-E only had persistent erythrocytosis requiring treatment with ACE inhibitors. CONCLUSIONS: Pathophysiology of post-transplant erythrocytosis is heterogeneous. In one-third of the patients, there was unexpected, spontaneous and transient growth of BFU-E which was not predictive of permanent erythrocytosis. The results of stem-cell studies suggest that in these cases erythrocytosis may be caused by defective regulation of erythroid progenitor proliferation, possibly due to particular cellular interactions or the effect of cyclosporin on erythropoiesis.

Adult↗
PubMed1998

Fibrotic entrapment of the small bowel in congenital intestinal lymphangiectasia.

Congenital intestinal lymphangiectasia is a rare protein-losing enteropathy that is characterized by diarrhea and peripheral edema. This report presents a 37-yr-old woman who had suffered from recurrent diarrhea and peripheral edema since her early childhood and who was admitted for severe attacks of abdominal pain. A diagnosis of intestinal lymphangiectasia was made endoscopically, histologically, and radiographically. Laparotomy revealed complete fibrotic entrapment of the small bowel, which caused partial mechanical bowel obstruction. Surgical decortication led to recovery. To the best of our knowledge, this is the first report on fibrotic entrapment of the small bowel in a patient with long lasting intestinal lymphangiectasia.

Adult↗
PubMed1998

EPIBACDIAL: a multicenter prospective study of risk factors for bacteremia in chronic hemodialysis patients.

Bacteremic infections are a major cause of mortality and morbidity in chronic hemodialysis patients. New developments in managing these patients (erythropoietin therapy, nasal mupirocin, long-term implanted catheters, and synthetic membranes) may have altered the epidemiologic patterns of bacteremia in dialysis patients. This multicenter prospective cross-sectional study was carried out to determine the current incidence of and risk factors for bacteremia in chronic hemodialysis patients in France. A total of 988 adults on chronic hemodialysis for 1 mo or longer was followed up prospectively for 6 mo in 19 French dialysis units. The factors associated with the development of at least one bacteremic episode over 6 mo were determined using the multivariate Cox proportional hazards model. Staphylococcus aureus (n=20) and coagulase-negative staphylococci (n=15) were responsible for most of the 51 bacteremic episodes recorded. The incidence of bacteremia was 0.93 episode per 100 patient-months. Four risk factors for bacteremia were identified: (1) vascular access (catheter versus fistula: RR=7.6; 95% CI, 3.7 to 15.6); (2) history of bacteremia (> or =2 versus no previous episode: RR=7.3; 95% CI, 3.2 to 16.4); (3) immunosuppressive therapy (current versus no: RR=3.0; 95% CI, 1.0 to 6.1); and (4) corpuscular hemoglobin (per 1 g/dl increment: RR=0.7; 95% CI, 0.6 to 0.9). Catheters, especially long-term implanted catheters, were found to be the leading risk factor of bacteremia in chronic hemodialysis patients. There was a trend toward recurrence of bacteremia that was not associated with chronic staphylococcal nasal carriage. Synthetic membranes were not associated with a lower risk of bacteremia in this population of well dialyzed patients, but anemia linked to resistance to erythropoietin appeared to be a possible risk factor for bacteremia.

Adolescent↗
PubMed1998

Amyloid and non-amyloid carpal tunnel syndrome in patients receiving chronic renal dialysis.

OBJECTIVE: To determine the prevalence of amyloid deposits among patients with carpal tunnel syndrome (CTS) receiving dialysis, and to investigate the factors associated with amyloid and non-amyloid CTS. METHODS: Subjects for this prospective study were dialysis patients who underwent surgery for CTS in the same surgical unit between 1989 and 1997. CTS was diagnosed from clinical and electromyographic (EMG) findings. Systematic standard radiographs and laboratory data were also obtained. Surgical investigations included systematic macroscopic examination and biopsy of the epineurium, flexor retinaculum, synovium, and flexor tendon sheaths. Samples were stained for amyloid and examined by plain and polarized light microscopy, immunohistochemistry, and electron microscopy. RESULTS: Forty-one samples from 30 patients (11 bilateral cases) were examined. Amyloid deposits were found in 26 samples from 18 patients (7 M, 11 F). Fifteen samples from 12 patients (3 M, 9 F) showed no amyloid deposits. Amyloid CTS was statistically significantly associated with arthralgia and longterm dialysis [mean 13.3 (range 5.5-23) vs 7.5 yrs (range 3 mo-14 yrs)] in non-amyloid CTS. Flexor tenosynovitis and carpal bone erosion occurred more frequently in amyloid CTS. There were no statistically significant differences between the 2 groups in clinical, laboratory or EMG findings, type of dialysis membrane, or frequency of ipsilateral fistula. Only amyloid CTS was recurrent. CONCLUSION: Amyloid deposits were confirmed microscopically in 63.4% of patients. The relatively large number of cases of non-amyloid CTS without signs of dialysis associated arthropathy suggests that CTS is not a satisfactory criterion for diagnosis of dialysis arthropathy or beta2-microglobulin amyloidosis unless the presence of amyloid has been confirmed or duration of dialysis treatment has been at least 15 years.

Adult↗
PubMed1998

[Dynamic MR-mammography in invasive lobular breast cancer].

PURPOSE: The objective of our study was to test the reliability of dynamic, contrast-enhanced MR-mammography (MR-M) in the detection of invasive lobular carcinoma (ILC) and to test if additional examination with MR-M increases the sensitivity of conventional mammography (Mx) in the detection of ILC. MATERIAL AND METHODS: We carried out 1,505 MR-Mammographies in 1,357 patients. Biopsy was indicated in 413 cases. Among the malignancies, 23/214 (10.7%) were ILC. MR-M was performed with a 1.0 T whole body MRI system with a dynamic FLASH-3D sequence. Relative signal enhancement within lesions detected and morphologic pattern of contrast enhancement (mep) were determined. Three types of mep were distinguished: type 1 without contrast enhancement, type 2 with focal contrast enhancement and type 3 with diffuse contrast enhancement of the glandular body. RESULTS: Within MR-M alone, 19/23 (82.6%) of ILC were detected due to a mep type 2. Four ILC were false negative on MR-M (2 cases show mep type 1 or mep type 3). The sensitivity of Mx alone was 86.9% (20/23). When both Mx and MR-M were combined, all 23 ILC were detected. The addition of MR-M to Mx may increase sensitivity to about 100% in the detection of ILC. CONCLUSION: Unsuspicuous MR-M (mep type 1) or diffuse uptake of contrast media (mep type 3) does not rule out malignancy in the presence of suspicious findings at Mx.

Aged↗
PubMed1998

[Adequate peritoneal dialysis: limitations of continuous ambulatory peritoneal dialysis (CAPD), place of automated peritoneal dialysis (APD)].

Recent epidemiological studies show a slowing down of the global growth of CAPD which is not compensated by the considerable development of APD. These modifications are the result of the arrival of technologies which allow new strategies as well as an improved knowledge of the adequate dialysis dose for PD. The re-evaluation of the adequate clearance targets show that CAPD does not deliver an adequate dialysis dose for anuric patients but it remains an excellent technique for patients with residual renal function. APD and mixed techniques (APD with automated diurnal exchange(s), CAPD with automated nocturnal exchange) can deliver an adequate dialysis dose if the peritoneal permeability is not too low and if the prescription is adapted to each patient. The growth of CAPD seems to be slowing down due to a better knowledge of its limitations. However the development of APD does not seem to be related to the increasing knowledge of its possibilities. The development of automated techniques, prescribed as substitute treatments, depends on a precise evaluation of the cost/efficiency/quality of life index, compared to the reference treatment which is iterative hemodialysis.

Humans↗
PubMed1998

[Preoperative marking of non-palpable mammary lesions on the magnetic resonance image using a body coil].

PURPOSE: To evaluate the efficacy of a MRI localization procedure using a non-dedicated body coil in lesions only visible in MRI. MATERIAL AND METHODS: In 18 patients, we performed a contrast enhanced (i.v. 0.2 mmol Gd-DTPA/kg b.w.) breast MRI on a 1.0 Tesla system (Magnetom Impact, Siemens, Erlangen, Germany) using a body coil and a GRE 3D sequence. In prone position, the patients were placed in a customized positioning device offering lateral access to the breast. The localizations were done with a MRI-compatible wire (n = 21). In addition, all patients underwent the same imaging protocol using a dedicated breast coil (without localization). For both MRI modalities, the signal intensities of the lesion, the normal breast tissue, and the background noise were measured. The lesion-to-fat contrast (LFC), the lesion-to-fat contrast (LFC), the lesion-to-breast tissue contrast (LBC) and the percentage of signal change pre and post contrast administration were calculated and compared. The localisation results were correlated to pathologic findings. RESULTS: There was no difference in lesion detection (lesion size: 0.5 to 1.2 cm) between the body coil and the dedicated breast coil. Regarding the LFC and LBC, the body coil was superior to the dedicated breast coil (no statistical significance). However, the background noise was higher using the body coil. In all cases the localisation was successful. CONCLUSION: In our preliminary experience, detection of breast lesions and wire-localization of the lesion by MRI is efficient and reliable using a non-dedicated body coil.

Adult↗
PubMed1997

[Value of early management of patients with chronic renal failure].

The objective of early referral in patients with chronic renal failure is to prevent complications as the disease progresses to the stage where dialysis or transplantation become necessary. Early diagnosis requires a systematic assessment of glomerular function in all patients with signs suggestive of renal disease. Screening programs are also recommended in populations at risk with vascular disease, diabetes, occupational exposure to nephrotoxic substances, or a potentially nephrotoxic treatment. Once stabilized, chronic renal failure usually progresses inevitably to end-stage disease. In France, the estimated annual incidence of chronic renal failure defined as creatininemia > 200 or 300 mumol/l is approximately 200 patients per million inhabitants and that of end-stage disease at 80 per million. Although access to replacement therapy is not limited in France, a certain number of patients are still seen at a late stage of the disease. When dialysis is initiated after the development of severe uremia, patients generally have a poor nutritional status, more severe acidosis and anemia and poorly controlled hypertension; the first dialysis session often occurs in an emergency setting. In this issue of La Presse Médicale, Jungers et al. demonstrate the higher morbidity and increased cost of the first hospitalization in patients without prior follow-up. An optimal treatment aimed at preserving renal function as long as possible can have a beneficial effect on preventing higher morbidity and mortality after beginning substitution therapy. Nephrology referral should be centered on controlling anemia with recombinant human erythropoietin, high blood pressure with appropriate drugs (particularly converting enzyme inhibitors), nutritional status with adapted protein-calorie intake, and renal osteodystrophy with calcium carbonate or recombinant growth hormone in children. Patients must also be prepared for definite dialysis both in terms of medical risk (hepatitis B vaccination) and psychosocial adaptation.

Adult↗
PubMed1997

[Pain intensity, mood and pain-alleviating actions in pre-chronic low back pain patients].

INTRODUCTION: The present study examines the correlations between pain intensity, mood and pain-alleviating actions in pre-chronic low back pain patients. The three variables were obtained with the Ulm Pain Diary (Ulmer Schmerztagebuch, UST). METHODS: Thirty-eight patients with low back pain described pain intensity, effect of pain on mood and medication as well as other therapies over a 3-week period (21 days). The patients had a history of pain for between 6 weeks and 6 months. Clinical and orthopedic examinations revealed no relevant organic findings explaining the pain process. RESULTS: Pain occurred on 18.1 (of 21) days. Half of the patients (n=19) used medication or took other actions against their pain. Correlations between the three variables demonstrated that all three were significantly related. Partial correlations showed in addition to a high correlation between pain intensity and mood, that the frequency of pain-relieving actions was far less related to pain intensity than to mood. The group that took actions against their pain had a higher level of pain intensity than the no-action group. Furthermore, the effect of pain on mood was significantly greater in this group than in the no-action group. CONCLUSION: The findings indicate that pain intensity, mood and actions against pain are highly correlated. When pain intensity is statistically controlled, the influence of mood on taking medication or other actions against pain becomes more pronounced. It can be concluded that self-initiated actions against pain depend much more on mood than on pain intensity in pre-chronic low back pain patients.

English Abstract↗