Biomedical subjects

J Beyer

Publications and source records attributed to J Beyer.

At least 91 records · Page 5Linked to original sources

PubMed2000

First-line high-dose chemotherapy +/- radiation therapy in patients with metastatic germ-cell cancer and brain metastases.

PURPOSE: To examine the feasibility and efficacy of first-line high-dose chemotherapy (HD-CTX) in patients with advanced metastatic germ-cell tumors (GCT) and brain metastases. PATIENTS AND METHODS: Twenty-two patients with brain metastases at initial diagnosis were identified within a cohort of two hundred thirty-one consecutive patients with advanced metastatic disease, entered on a German multicenter trial between January 1993 and July 1998. All patients received first-line HD-CTX with cisplatin-etoposide-ifosfamide (HD-VIP) followed by autologous stem-cell transplantation. Brain irradiation (BRT) with 30-50 Gy +/- 10 Gy boost was applied in patients with symptomatic CNS disease or as consolidation in case of residual CNS lesions after HD-CTX. RESULTS: A median number of 4 HD-CTX cycles (range 2-5) were applied to the 22 patients. Ten patients received HD-CTX alone and twelve patients were treated with HD-CTX plus BRT. Median duration of WHO grade 4 granulocytopenia and thrombocytopenia was seven and five days after each cycle, respectively. Non-hematologic toxicity consisted mainly of mucositis/enteritis (WHO grade 3-4 32%). Two early deaths occurred in twenty-two patients (one CNS-bleeding/one sepsis). Fourteen of twenty patients achieved a CR/PRm- status. Twenty patients (91%) responded in the brain (55% CR/36% PR). Two-year progression-free and overall survival rates were 72% and 81%, respectively. These survival rates are substantially higher compared to the available data in the literature. CONCLUSIONS: High-dose chemotherapy with autologous stem-cell support +/- BRT appears to be feasible without increased therapy-related mortality in patients with advanced metastatic GCT and brain metastases. The results achieved emphasize the high chemosensitivity of CNS metastases from GCT and suggest a potential role for dose intensification. The dose of BRT in addition to HD-CTX may be tailored to the presence of clinical symptoms and the response of CNS metastases to chemotherapy.

Adult↗

PubMed2000

Diagnosis of toxoplasmosis in bone marrow transplant recipients: comparison of PCR-based results and immunohistochemistry.

Toxoplasmosis in bone marrow transplant recipients is a rare but serious complication and if untreated, almost uniformly fatal. The diagnosis, however, remains difficult. We therefore compared serial determination of antibody titers specific for T. gondii before and after transplantation, serial PCR for T. gondii DNA in serum, PCR and nested PCR for T. gondii DNA in various tissues, conventional histology and immunohistochemistry for detection of parasites in three patients with autopsy-confirmed toxoplasmosis after bone marrow transplantation. Immunohistochemistry demonstrated the presence of parasites in 13 out of 20 organs investigated (65%), whereas PCR detected T. gondii-specific DNA in 15 out of 20 organs (75%). Immunohistochemistry revealed concordant results to PCR data in 60% of the specimens. With the use of a nested PCR protocol, eight out of nine samples (89%) were positive for T. gondii-specific DNA. The combination of both methods detected the presence of parasites in 90% of the specimens. Serial PCR in serum did not yield positive results. Neither PCR nor immunohistochemistry was able to detect parasites in all organs investigated, but both methods together improved sensitivity to 90% and consequently, should be used jointly to maximize diagnostic precision. Bone Marrow Transplantation (2000) 25, 1257-1262.

Adult↗

PubMed2000

Porcine reproductive and respiratory syndrome virus (PRRSV): kinetics of infection in lymphatic organs and lung.

Pigs were infected by the oronasal route with European isolates of the porcine reproductive and respiratory syndrome virus (PRRSV; I10 and Cobbelsdorf). The kinetics of infection in lymphatic organs and the lung were analysed by immunofluorescence detection of virus antigen, re-isolation of the virus and reverse transcription--polymerase chain reaction (RT-PCR) for PRRSV-specific RNA. The kinetics of PRRSV infection proceeded in three phases, irrespective of the varying infestation of lymphatic organs within the first days post-infection (p.i.). First, an early acute infection of lymphatic organs developed within the first week and was characterized by a high number of antigen-positive macrophages. Second, a delayed acute infection of the lung was observed, which was most pronounced during the second and third week p.i. when a high number of infected alveolar macrophages was observed. The acute infection of lymphatic organs had resolved at this time. Infected cells in the lung were predominantly located in pneumonic lesions. Third, a persistent infection was demonstrated by RT-PCR and immunohistology when the experiments were terminated at day 49 p.i. The virus persisted in lymphatic organs, especially in the tonsils, and in the lung. At this stage, indications for a re-occurrence of acute infection were observed in restricted areas of the lung.

Animals↗

PubMed2000

Serum levels of substance P are decreased in patients with type 1 diabetes.

Morphological and immunohistochemical studies in diabetic subjects have shown a depletion of the neuropeptide substance P (SP) in the central and peripheral nervous system. This is the first study investigating serum levels of substance P in type 1 diabetes patients (n=50) and controls (n=75) by means of an enzyme immunoassay. The serum level of SP was significantly decreased in the diabetic group compared to the control group (10.12+/-0.29 vs. 12.25+/-0.38 pg/ml; p<0.0001). In diabetic patients, there was no correlation of substance P levels with age, serum creatinine, albuminuria, total cholesterol, HDL- or LDL-cholesterol, triglycerides, HbA1c, type or duration of diabetes and gender. Furthermore, there was no difference in serum levels of SP in patients with or without retinopathy, but SP was significantly decreased in patients with neuropathy (9.59+/-0.48 vs. 10.78+/-0.83 pg/ml; p=0.04). These data show that SP is decreased in serum of type 1 diabetes patients, especially in those with diabetic neuropathy. Subsequent and already ongoing prospective studies in well validated diabetic patients with neuropathy may characterize the impact of this neurogenic marker in the course of diabetic neuropathy.

Adolescent↗

PubMed2000

Decreased plasma concentrations of L-hydroxy-arginine as a marker of reduced NO formation in patients with combined cardiovascular risk factors.

Patients with metabolic syndrome represent a group with extensive cardiovascular risk factors for the development of atherosclerosis, which may be preceded by an impairment of endothelial function. Endothelial dysfunction is characterized by a reduced availability of bioactive nitric oxide, the principal mediator of endothelium-dependent vasodilation. In the present study we assessed NO synthesis in vivo by measuring the NO-related amino acids L-arginine and L-citrulline and in particular the stable intermediate compound N(omega)-hydroxy-L-arginine (L-NHA) in patients with metabolic syndrome by using high-performance liquid chromatography (HPLC) analysis. As a prerequisite to our study, we measured the amino acid concentrations in 31 healthy volunteers to investigate gender and age differences. To prove whether blood drawn from peripheral veins reflects plasma concentrations of the whole vessel system, several blood samples from different regions were obtained from patients undergoing elective left and right heart catheterization. In the latter group, no significant differences were noted among the plasma concentrations between the different sample sites. In healthy volunteers, there were no significant differences in plasma concentrations of any one specific amino acid between males and females or age groups. The main finding of the study is that the intermediate product of NO synthesis, L-NHA, is significantly reduced in the plasma samples of patients with a metabolic syndrome as compared with samples from healthy control subjects. The plasma concentrations of the NO precursor L-arginine and the end product of NO synthesis, L-citrulline, were unchanged. In conclusion, our results suggest that plasma levels of L-NHA are independent of age and gender and are not different at various locations within the vascular system. In a group of patients at high risk for the development of atherosclerosis, we found reduced plasma concentrations of L-NHA, either caused by a decreased endothelial NO synthase activity or caused by an increased breakdown of L-NHA by pathways independent of NO synthase, resulting in a reduced availability of L-NHA for NO synthesis.

Adult↗

PubMed2000

Phase II study of bendamustine in patients with relapsed or cisplatin-refractory germ cell cancer.

Despite generally high cure rates in patients with metastatic germ cell cancer, patients with incomplete response to first-line cisplatin-based chemotherapy or with relapsed disease following high-dose salvage therapy exhibit a very poor prognosis. We investigated the efficacy and toxicity of bendamustine, a bifunctional alkylating benzimidol derivative with only partial cross-resistance to other alkylating agents such as ifosfamide or cyclophosphamide. Nineteen patients with cisplatin-refractory germ cell tumors (GCT) or relapse after high-dose chemotherapy plus autologous stem cell support were treated with bendamustine at a dose of 120 mg/m2 on 2 consecutive days at 3 week intervals. Patients had received a median of 9 (range 4-20) platinum-containing treatment cycles prior to bendamustine and 13 patients (68%) had previously received carboplatin/etoposide-based high-dose chemotherapy. One patient achieved a partial remission of only 6 weeks duration. No other responses were seen. Toxicity was low with one patient developing WHO grade 3 thrombocytopenia as the only WHO grade 3/4 toxicity observed. Hematologic toxicity was similar in patients pretreated with and without high-dose chemotherapy plus autologous stem cell support. We conclude that bendamustine has little or no clinically relevant activity in patients with cisplatin-refractory GCT or relapsed disease after high-dose chemotherapy.

Adult↗

PubMed2000

Pseudorabies virus expressing bovine herpesvirus 1 glycoprotein B exhibits altered neurotropism and increased neurovirulence.

Herpesvirus glycoproteins play dominant roles in the initiation of infection of target cells in culture and thus may also influence viral tropism in vivo. Whereas the relative contribution of several nonessential glycoproteins to neurovirulence and neurotropism of Pseudorabies virus (PrV), an alphaherpesvirus which causes Aujeszky's disease in pigs, has recently been uncovered in studies using viral deletion mutants, the importance of essential glycoproteins is more difficult to assess. We isolated an infectious PrV mutant, PrV-9112C2, which lacks the gene encoding the essential PrV glycoprotein B (gB) but stably carries in its genome and expresses the homologous gene of bovine herpesvirus 1 (BHV-1) (A. Kopp and T. C. Mettenleiter, J. Virol. 66:2754-2762, 1992). Apart from exhibiting a slight delay in penetration kinetics, PrV-9112C2 was similar in its growth characteristics in cell culture to wild-type PrV. To analyze the effect of the exchange of these homologous glycoproteins in PrV's natural host, swine, 4-week-old piglets were intranasally infected with 10(6) PFU of either wild-type PrV strain Kaplan (PrV-Ka), PrV-9112C2, or PrV-9112C2R, in which the PrV gB gene was reinserted instead of the BHV-1 gB gene. Animals infected with PrV-Ka and PrV-9112C2R showed a similar course of disease, i.e., high fever, marked respiratory symptoms but minimal neurological disorders, and excretion of high amounts of virus. All animals survived the infection. In contrast, animals infected with PrV-9112C2 showed no respiratory symptoms and developed only mild fever. However, on day 5 after infection, all piglets developed severe central nervous system (CNS) symptoms leading to death within 48 to 72 h. Detailed histological analyses showed that PrV-9112C2R infected all regions of the nasal mucosa and subsequently spread to the CNS preferentially by the trigeminal route. In contrast, PrV-9112C2 primarily infected the olfactory epithelium and spread via the olfactory route. In the CNS, more viral antigen and significantly more pronounced histological changes resulting in more severe encephalitis were found after PrV-9112C2 infection. Thus, our results demonstrate that replacement of PrV gB by the homologous BHV-1 glycoprotein resulted in a dramatic increase in neurovirulence combined with an alteration in the route of neuroinvasion, indicating that the essential gB is involved in determining neurotropism and neurovirulence of PrV.

Animals↗

PubMed2000

Improved diagnostic methods in the follow-up of medullary thyroid carcinoma by highly specific calcitonin measurements.

Calcitonin (CT) is an important tumor marker for medullary thyroid carcinoma (MTC). Recent CT assays chiefly recognize the monomeric form of CT (mCT). It was the objective of this study to examine the consequences of the higher specificity of the assay for interpretation of the postoperative CT values in MTC patients. The postoperative mCT concentration was measured in 214 patients with differentiated thyroid carcinoma (MTC excepted; non-MTC patients) to determine a reference range of mCT in totally thyroidectomized patients. Monomeric CT was also determined with a two-site chemiluminescence immunoassay (Nichols) in 94 healthy subjects and in 68 MTC patients. The mCT concentrations were below the detection limit in all examined completely thyroidectomized non-MTC patients. Basal and stimulated mCT values were also below the detection limit in 32 of the 68 MTC patients. The biochemical and imaging diagnosis of the latter patients did not give any indication of tumor recurrence. We conclude that completely thyroidectomized patients with non-MTC do not show any measurable mCT concentrations. In comparison with an unspecific CT-RIA, the more specific mCT determination by immunoluminometric assay permits a more precise differentiation between postoperative normal and pathological values and an earlier diagnosis of recurrent MTC.

Adult↗

PubMed2000

Effects of proinsulin C-peptide on nitric oxide, microvascular blood flow and erythrocyte Na+,K+-ATPase activity in diabetes mellitus type I.

This study was conducted to evaluate the influence of proinsulin C-peptide on erythrocyte Na(+),K(+)-ATPase and endothelial nitric oxide synthase activities in patients with type I diabetes. In a randomized double-blind study design, ten patients with type I diabetes received intravenous infusions of either human C-peptide or physiological saline on two different occasions. C-peptide was infused at a rate of 3 pmol.min(-1).kg(-1) for 60 min, and thereafter at 10 pmol.min(-1).kg(-1) for 60 min. At baseline and after 60 and 120 min, laser Doppler flow (LDF) was measured following acetylcholine iontophoresis or mild thermal stimulation (44 degrees C), and venous blood samples were collected to determine plasma cGMP levels and erythrocyte membrane Na(+),K(+)-ATPase activity. The LDF response to acetylcholine increased during C-peptide infusion and decreased during saline infusion [18.6+/-19.2 and -13.2+/-9.4 arbitrary units respectively; mean+/-S.E.M.; P<0.05). No significant change in LDF was observed after thermal stimulation. The baseline plasma concentration of cGMP was 5.5+/-0.6 nmol.l(-1); this rose to 6.8+/-0.9 nmol.l(-1) during C-peptide infusion (P<0.05). Erythrocyte Na(+),K(+)-ATPase activity increased from 140+/-29 nmol of P(i).h(-1).mg(-1) in the basal state to 287+/-5 nmol of P(i). h(-1).mg(-1) during C-peptide infusion (P<0.01). There was a significant linear relationship between plasma C-peptide levels and erythrocyte Na(+),K(+)-ATPase activity during the C-peptide infusion (r=0.46, P<0.01). No significant changes in plasma cGMP levels or Na(+),K(+)-ATPase activity were observed during saline infusion. This study demonstrates an effect of human proinsulin C-peptide on microvascular function, which might be mediated by an increase in NO production and an activation of the erythrocyte Na(+),K(+)-ATPase. These mechanisms are compatible with the previous observed microvascular effects of C-peptide in patients with type I diabetes.

Acetylcholine↗

PubMed2000

Comparison of immunoassays for the detection of anti-GAD65 autoantibodies in patients with diabetes mellitus.

Recent studies have demonstrated that a combination of GAD-antibody assays and IA-2 autoantibody assays show a high diagnostic specificity for Type 1 diabetes. For this reason there is increasing interest in the use of GAD-antibody measurement for Type 1 risk assessment. Since a number of different assays have been published and documented in the literature, the aim of this study was to evaluate four different anti-GAD test systems that are commercially available in Germany. We tested the anti-GAD prevalences in five patient groups with the different immunoassays and compared them with the values obtained by an immunoprecipitation test (IP-Test). All assays correlated well with the IP-test and showed high sensitivity and specificity in the group of patients with recent onset Type 1 diabetes and the control group. The groups tested consisted of 20 subjects with recent onset Type 1 diabetes (< 6 weeks) (sensitivity 70-90%), nine subjects with a Type 1 duration of more than 2 years (sensitivity 11-33%), 21 patients with pluriglandular insufficiency (sensitivity 28.5-47.5%), 10 patients with Type 2 (specificity: 90-100%), and 14 healthy control subjects (specificity: 93-100%). Our data show a high level of sensitivity and specificity of the tested, commercially available, assays. Since almost every laboratory should be able to establish one of these assays, this may facilitate the possibility of further large scale population studies with the aim of investigating GAD-antibody prevalences in screening for Type 1 diabetes. Increased measurement of the diabetes-associated antibodies will be helpful in the differential diagnosis of gestational diabetes mellitus (GDM) and latent autoimmune diabetes of the adult (LADA).

Adolescent↗

PubMed2000

Detection of germ-cell tumor cells in peripheral blood progenitor cell harvests: impact on clinical outcome.

Our study was conducted to evaluate the impact of tumor cell contamination in peripheral blood progenitor cell (PBPC) harvests on the clinical outcome of patients with germ-cell tumors undergoing high-dose chemotherapy (HDCT) and autologous PBPC reinfusion. Samples of mononuclear cells from progenitor cell harvests of 57 patients with advanced or recurrent germ-cell tumors were retrospectively screened for contaminating tumor cells using immunocytochemical staining for cytokeratin filaments and reverse transcription-PCR (RT-PCR) testing for germ-cell alkaline phosphatase mRNA. The results were correlated to clinical prognostic variables as well as to the overall and event-free survival of these patients. Tumor cell contamination was detected in PBPC harvests of 16 of 57 enrolled patients (28%), and, among these, in 14 of 51 (27%) who underwent HDCT. The presence of contaminating tumor cells as detected by either immunocytochemical staining, RT-PCR, or both was strongly associated with a reduced overall survival (43% versus 71%, P = 0.0037) and event-free survival (0% versus 52%, P = 0.0005) after 1 year. In multivariate analysis, the demonstration of contaminating tumor cells had a higher predictive value for a poor event-free survival than other known prognostic variables. The presence of contaminating tumor cells in PBPC harvests of patients with germ-cell tumors seems to predict a poor overall and event-free survival in patients undergoing HDCT and autologous PBPC reinfusion.

Adult↗

PubMed1999

High-dose salvage chemotherapy. Germ-cell tumor treatment results in Germany.

During the past 10 years, high-dose chemotherapy (HDCT) has emerged as a feasible and curative treatment option for patients with multiply relapsed and/or refractory germ-cell tumors. Increasing experience and the results from clinical trials have helped to optimize the application of HDCT and to define its role in the salvage concepts for germ-cell tumors.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1999

Treatment of patients with cisplatin-refractory testicular germ-cell cancer. German Testicular Cancer Study Group (GTCSG).

With the use of cisplatin-based combination chemotherapy, metastatic testicular germ-cell tumors can be cured in 70% to 80% of patients. The combination of cisplatin, etoposide and bleomycine (PEB) is considered standard therapy. Patients refractory to cisplatin-based chemotherapy have a markedly poor prognosis. Several chemotherapeutic agents have been evaluated in intensively pre-treated or cisplatin-refractory patients. Neither the anthracyclines nor vinorelbine, topotecan or biological agents such as suramin and retinoic acid have demonstrated clinical activity. Paclitaxel has been evaluated at different doses and schedules and yielded a response rate of 21% (range 11-30%), with single patients achieving complete remissions. This has led to the inclusion of paclitaxel in salvage regimens in combination with cisplatin and/or ifosfamide. Two studies have evaluated gemcitabine in refractory germ-cell tumors and demonstrated a response rate of 17% (95% CI 7-28%) in 52 intensively pre-treated patients, two-thirds of whom had relapsed after previous high-dose chemotherapy plus autologous stem-cell transplantation. The non-hematological toxicity of weekly gemcitabine at doses of 1,000 to 1,250 mg/m2 was tolerable, and hematological side effects included thrombocytopenia in approximately 20% of patients. Ongoing studies in refractory germ-cell tumors performed by the German Testicular Cancer Study Group are evaluating bendamustine, an alkylating agent with activity in breast and small-cell lung cancer, and oxaliplatin, a platinum derivative with incomplete cross-resistance to cisplatin. Future trials combining new active agents may examine alternating treatment strategies in patients with poor-prognostic disease or as salvage treatment.

Antimetabolites, Antineoplastic↗

PubMed1999

[Polyglandular autoimmune syndrome type II: epidemiology and forms of manifestation].

BACKGROUND AND OBJECTIVE: Polyglandular autoimmune syndrome (PAS), is characterized by the coexistence of several autoimmune diseases, affecting predominantly the endocrine glands. The juvenile form (PAS type I) is distinguished from the adult type II in which autoimmune thyroiditis, adrenal cortical insufficiency and diabetes mellitus type I predominate. The connections between epidemiological, clinical and immunological aspects were analysed and described in this study of patients with PAS type II. PATIENTS AND METHODS: Among a total patient population of over 15,000 seen in our endocrinological university policlinic from 1992 through 1996, the clinical data of all 151 patients with PAS type II were analysed retrospectively. RESULTS: Of the 151 patients with PAS 37 were male (aged 16-74 years, median 42 years) and 114 female (aged 16-84 years; median 46 years), a prevalence of 1:100, 92 patients (61%) had diabetes mellitus type I (78% males, 55% females; p = 0.013), 50 (33%) had hyperthyroidism (32% and 33%; difference not significant), 49 had Hashimoto's thyroiditis (14% and 39%; p = 0.005) and 28 (18.5% had Addison's disease (14% males, 20% females; n.s.). Vitiligo was less common, occurring in 30 (20%), alopecia in 9 (6%), pernicious anaemia in 5 (5%) and hypogonadism in 8 (5%). The most common combination was diabetes type I with thyroiditis (33%), the time between manifestations of each disease being highly variable, diabetes was the first manifestation in half the cases. Partial cell antibodies were present in 62 patients (54%), and 52% had positive thyroid-associated antibodies without manifest signs of thyroid disease. CONCLUSION: PAS occurs relatively often among patients of an endocrinological centre, with a 3:1 female to male ratio. Because there is usually a long interval between the onset of the various endocrine diseases, regular monitoring of patients with an endocrine autoimmune disease is indicated, specific tests to be performed if additional immune diseases are suspected.

Addison Disease↗

PubMed1999

Aerosolized amphotericin B inhalations as prophylaxis of invasive aspergillus infections during prolonged neutropenia: results of a prospective randomized multicenter trial.

We performed a prospective, randomized, multicenter trial to evaluate the effectiveness of prophylactic inhalations with aerosolized amphotericin B (aeroAmB) to reduce the incidence of invasive aspergillus (IA) infections in patients after chemotherapy or autologous bone marrow transplantation and an expected duration of neutropenia of at least 10 days. From March 1993 until April 1996, 382 patients with leukemias, relapsed high-grade non-Hodgkin lymphomas, or solid tumors were randomized with a 13:10 ratio to receive either prophylactic aeroAmB inhalations at a dose of 10 mg twice daily or no inhalation prophylaxis in an unblinded fashion. The incidence of proven, probable, or possible IA infections was 10 of 227 (4%) in patients who received prophylactic aeroAmB. This did not differ significantly from the 11 of 155 (7%) incidence in patients who received no inhalation prophylaxis (P =.37). Moreover, no differences in the overall mortality (13% v 10%; P =.37) or in the infection-related mortality (8% v 7%; P =.79) were found. In contrast to other nonrandomized trials, we observed no benefit from prophylactic aeroAmB inhalations, but the overall incidence of IA infections was low.

Administration, Inhalation↗

PubMed1999

The effect of human proinsulin C-peptide on erythrocyte deformability in patients with Type I diabetes mellitus.

AIMS/HYPOTHESIS: In recent years, evidence has arisen that proinsulin C-peptide exerts biological effects especially on microcirculation, e.g. C-peptide has been shown to increase skin microcirculation in patients with Type I (insulin-dependent) diabetes mellitus and to activate endothelial nitric oxide synthase. This study aimed to investigate the influence of pro-insulin C-peptide on erythrocyte deformability which was assessed by means of laser diffractoscopy. METHODS: Blood samples from healthy control subjects (n = 10) and Type I diabetic patients (n = 15) completely deficient of C-peptide were analysed at shear stresses ranging from 0.3 to 30 Pa. RESULTS: Erythrocyte deformability was lower in the group of Type I diabetic patients than in the control subjects. Preincubation of the diabetic blood samples with various concentrations of human proinsulin C-peptide for 8 h restored the deformability of erythrocytes, almost reaching the values of control samples. In contrast, proinsulin C-peptide did not modify the erythrocyte deformability of control subjects. CONCLUSION/INTERPRETATION: We conclude that proinsulin C-peptide is able to ameliorate the impaired deformability of erythrocytes in Type I diabetic patients and we hypothesise that this effect is mediated by restoration of Na(+)-K(+)-ATPase activity, which is known to be attenuated in diabetic patients.

C-Peptide↗

PubMed1999

Confocal laser scanning microscopy: A nondestructive subsurface histotomography of healthy human bone.

Microscopy of bony tissue usually requires special treatment for decalcification and processing of thin sections. Confocal laser scanning microscopy (CLSM) allows the nondestructive histotomography of organic hard tissue. The aim of this study was to visualize healthy human bone structures and to correlate identical areas in CLSM and conventional light microscopy. Each sample of healthy human lower jaw (n = 20) was divided into three parts: (1) fresh, untreated bony blocks studied by CLSM; (2) MMA-embedded thin sections (without decalcification), HE stained and studied by CLSM and conventional light microscopy (correlation of identical areas); (3) decalcificated, HE stained, histological sections studied by conventional light microscopy. In untreated bony blocks, microstructures such as osteocytes and lamellae were identified by CLSM. These structures could be correlated with conventional light microscopy. In CLSM, subcellular structures cannot yet be interpreted, whereas cytoplastic processes of osteocytes were seen with high contrast. With CLSM, nondestructive histology of cortical bone can be obtained. The risk of artifacts due to pretreatment is minimized, and subsurface visualization does not affect the interpretation.

Histological Techniques↗

PubMed1999

Serum leptin is associated with serum uric acid concentrations in humans.

This cross-sectional study aimed to evaluate the relationship between leptin and the cluster of abnormalities often referred to as the metabolic syndrome. The serum leptin concentration, body mass index (BMI), percent body fat, total fat mass (FM), waist and hip circumference, waist to hip ratio (WHR), prevalence of hypertension, and triglyceride (TG), lipoprotein, and uric acid concentration were determined in 86 type 2 diabetic (n = 59) and healthy (n = 27) subjects. Multiple regression analyses showed that the estimates of total body obesity (BMI, percent body fat, and total FM), sex, and serum uric acid concentration are independently associated with the serum leptin concentration. The finding of a positive correlation between serum leptin and uric acid levels suggests that leptin could be a pathogenic factor responsible for hyperuricemia in obesity.

Adipose Tissue↗