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Biomedical subjects

M Herman

Publications and source records attributed to M Herman.

At least 19 recordsLinked to original sources
PubMed2006

Elevated serum alkaline phosphatase levels in a renal transplant patient precede colitis.

An asymptomatic, but highly significant, rise in serum alkaline phosphatase (AP) levels developed in a renal transplant recipient. Investigations ruled out bony or hepatobiliary disease. Subsequent diarrhea and weight loss led to a diagnosis of cytomegalovirus (CMV) colitis, which was confirmed with a positive CMV pp65 antigenemia test and an endoscopic finding of multiple colonic erosions. Intravenous ganciclovir led to complete patient recovery and a swift reduction of serum AP levels to normal. Normally, intestinal AP isoenzymes are cleared quickly from the circulation. However, acute bowel diseases, especially when inflammatory in origin, can produce high serum AP levels. In this presented patient, the rise in serum AP levels preceded symptomatic manifestations of CMV colitis, and fell with successful therapy. Acute CMV disease in solid organ transplant recipients is common, can take many shapes, and needs to be diagnosed quickly. An unexplained rise in serum AP levels should lead to a search for inflammatory bowel disease, specifically CMV colitis, in transplanted patients.

Adult↗
PubMed2005

The vibrational energy pattern in acetylene VII: (12)C(13)CH2.

In (12)C(13)CH(2) 129 vibrational term values up to 10,000 cm(-1) are merged, about 60% of which are newly reported. They are fitted using an effective Hamiltonian with a standard deviation of 0.22 cm(-1). The vibrational assignments and vibrational constants are listed and discussed. The energy pattern is found to be very similar to the one in (12)C2H2 with additional anharmonic resonances arising from the lack of u/g character in the asymmetric isotopolog.

Journal Article↗
PubMed2005

CT colonography with fecal tagging after incomplete colonoscopy.

The objective of this study was to evaluate dietary fecal tagging (FT) as a cleansing method prior to CT colonography (CTC) in patients with incomplete conventional colonoscopy (CC). After written informed consent was obtained, 24 patients had standard colonoscopic preparation (ScCl), and 25 patients had FT as cleansing method. Segmental distention, fluid levels, fecal residues, tagged appearance of fluid levels, and residual stool were evaluated. Mann-Whitney U test was used to test for significant differences between FT and ScCl groups. Compared with ScCl, FT improved distention (p=0.001), reduced the amount of fluid (p=0.043), but suffered from residual stool (p=0.046). A clear correlation was found between distention and fluid. No differences were found in stool size between FT and ScCl. FT showed a good labeling of fecal residues, and acceptable labeling of fluid levels. Compared with ScCl, FT reduces fluid, favors distention, but suffers from fecal residues. The tagged nature of these residues, however, allows differentiation from polyps.

Adult↗
PubMed2005

Implications of a genomic search for autophagy-related genes in trypanosomatids.

Autophagy is the process by which cellular components are directed to and degraded in the vacuole or lysosome and has been studied largely in yeasts. We present here an in silico genomic analysis of trypanosomatid autophagy aimed at highlighting similarities and differences with autophagy in other organisms. Less than half of the yeast autophagy-related proteins examined have certain putative orthologues in trypanosomatids. A cytosol-to-vacuole transport system is clearly lacking in these organisms. Other absences are even more unexpected and have implications for our understanding of the molecular mechanisms of autophagy. The results are consistent with taxon-specific addition of components to a core autophagy machinery during evolution.

Animals↗
PubMed2004

MEG response to median nerve stimulation correlates with recovery of sensory and motor function after stroke.

OBJECTIVE: Hemiparesis due to damage by stroke in primary motor cortex (MI) or its underlying projections presents a problem for functional neuroimaging technologies that attempt to evaluate the neurophysiological basis for restoration of motor function. Traditional assessments of MI function require patients to move their fingers, hands, or limbs, which can be either impossible or markedly compromised after stroke. We recently demonstrated in normal subjects that magnetoencephalography (MEG), a non-invasive neuromagnetic functional imaging technique, detects neuronal response elicited by electrical median nerve stimulation in MI, as well as primary somatosensory cortex (SI). In the present study, we used the MEG response from median nerve stimulation to investigate the recovery of primary motor and somatosensory in acute ischemic stroke patients. METHODS: Twelve patients with unilateral ischemic strokes that affected sensorimotor functions of their hand were studied in the acute stage (4.4+/-1.2 days, mean+/-SD) and during a 1-month follow-up (38.6+/-5.6 days, except for one patient's follow-up done 6 month after stroke). RESULTS: Among the multiple cortical sources localized after median nerve stimulation, one source localized to SI and another localized to the vicinity of MI. Changes in the source strengths of the first component post-stimulus of MI and SI correlated with the extent of recovery of sensorimotor functions as determined by neurological exams. CONCLUSIONS: This study provides a novel way of indirectly assessing MI function using MEG during the acute stroke phase, when many patients often cannot perform motor tasks due to paralysis.

Adult↗
PubMed2004

[Complications of extended lung resection procedures following the neoadjuvant therapy].

UNLABELLED: Local tumor expansion in the sense of the tumor invasion into the extrapulmonary structures, which must be removed in one step, preferably en-bloc, together with the primary tumor, is the reason for extending the lung resection procedure. Although verified lymphogenic metastasing into either unilateral, eventually into contralateral mediastinal lymphonodes (stage N2 resp. N3, according to the TNM), remains the commonest indication for the induction therapy in cases of the lung carcinoma, application of the neoadjuvant therapy in cases when extended resections may be expected, is indicated in case the tumor expands into the surrounding structures, which signifies opening of new, unnatural routes of possible lymphogenic and haematogenic dissemination, and thus, a significantly higher risk of the surgical therapy failure. During the period 1995-2002, our team conducted 15 extended lung resection procedures following the preceding induction therapy in patients suffering from the IIB-IIIB stage of the non-small cellular lung carcinoma (NSCLC). The 30-day lethality rate equalled zero. We recorded two rare complications and the postoperative morbidity was acceptable. CONCLUSION: Exhausting staging, the best possible prediction of the tumor behaviour following the surgical procedure and minimal surgical complications remain the prerequisite for good long-term results following the extended lung resections for the lung carcinoma. Application of the neoadjuvant therapy prior to the resection procedure need not increase the risk of surgical complications and, furthermore, may positively affect the disease prognosis.

Carcinoma, Non-Small-Cell Lung↗
PubMed2004

[Extent of lymphadenectomy in lung resection for carcinoma].

Dissemination of the bronchogenic carcinoma into the lung and mediastinal lymphonodes is considered one of the basic prognostic factors. Correct evaluation of the lymphonodes involvement remains the principal pre-requisite for the choice of the most appropriate procedure and makes a forecast of a particular patient's perspective possible. The preoperative diagnostics of malignant lymphadenopathy is based on a CT examination. Once enlarged lymphonodes are detected, invasive exploration is indicated--either via mediastinoscopy, eventually via thoracoscopy. The final picture of the extent of the tumor dissemination via lymphatics is provided by the final histopathological examination of the lymphonodes removed during the surgical procedure. The minimal extent of lymphadenectomy is still being discussed. Some clinics do not conduct it at all. On the other hand, there are some clinics, where the en-bloc mediastinal lymphonodes dissection remains a common procedure during all lung carcinoma surgical procedures. On the group of 226 patients operated between 1996-1999, the authors assess surgical aspects and complications of the lymphadenectomic procedure within the radical lung resection for the non-spinocellular lung carcinoma. In the subgroup of 73 patients with a confirmed malignancy of the lung lymphonodes, the authors have found no statistical difference in the five-year survival rate which would be connected to lymphadenectomy. Mediastinal lymphadenectomy, with respect to its sound diagnostic and prognostic benefits, remains a necessary part of any curative resection. It proved to improve local control of the tumor, however, it has no clear influence on the survival rate. In small peripheral tumors (T1, T2), its extent may be restricted to systematic sampling of the interlobium, lung hilus and medistinum lymphonodes. On the other hand, in case of advanced tumors after the induction therapy, no other than en-block resection procedures are suitable or even possible.

Carcinoma, Bronchogenic↗
PubMed2003

Phase I study of escalating doses of low-dose-rate, locoregional irradiation preceding Cytoxan-TBI for patients with chemotherapy-resistant non-Hodgkin's or Hodgkin's lymphoma.

PURPOSE: In patients in whom bone marrow transplantation (BMT) fails, recurrence often occurs at sites known to have contained disease before initiating BMT. The purpose of this study was to find the maximal tolerable dose of locoregional irradiation (LRT) between 1000 and 2000 cGy that could be integrated with our Cytoxan-total body irradiation (TBI) BMT conditioning regimen in the treatment of lymphoma. METHODS AND MATERIALS: Patients had Hodgkin's or non-Hodgkin's lymphoma in chemotherapy-refractory relapse. All patients received LRT to a maximum of three sets of fields encompassing either all current or all previously known sites of disease. Cytoxan-TBI consisted of cyclophosphamide 50 mg/kg daily for 4 days followed by TBI of 1200 cGy given in four fractions. RESULTS: Twenty-one patients were enrolled. Radiation Therapy Oncology Group Grade 3 in-field acute toxicity was observed in 1 patient at each dose level up to 1500 cGy and in 3 of 6 patients receiving 2000 cGy. Clinically evident late toxicities were limited to hypothyroidism and one second malignancy occurring outside the LRT fields. CONCLUSION: Low-dose-rate, LRT with concurrent Cytoxan-TBI before BMT has acceptable rates of in-field toxicity for doses up to 1500 cGy in five fractions. This regimen safely permits the use of a total combined radiation dose of up to 2700 cGy during 2 weeks, with encouraging in-field response rates in treatment-refractory patients.

Adolescent↗
PubMed2003

[Importance of neoadjuvant chemotherapy in the treatment of advanced bronchogenic carcinoma].

BACKGROUND: The basic task of induction (neo-adjuvant) therapy is elimination of occult micrometastatic dissemination found in some cases already in localized stages of non-small cell pulmonary cancer (stage I-IIIA NSCLC). An equally important effect is also cytoreduction in primary tumours which have before the local intervention an intact vascular supply. A difficult problem remains the correct selection of patients who from the long-term aspect may profit from such a procedure. MATERIAL AND METHODS: The authors evaluated perspectively aspects of oncological treatment and circumstances of surgical intervention after induction chemotherapy in 81 and 87 patients resp. in stage IIIA NSCLC evaluated before initiated neo-adjuvant chemotherapy. RESULTS: Complete remission was recorded in 4.9%, partial remission in 50.6%, stabilized disease in 23.5% and progression in 21% patients. Down-staging was recorded in 26%, 70.3% patients were indicated for surgery. In the group of 87 patients operated after induction therapy pneumonectomies predominated--41 (46%), only one operated patient died within 30 days after surgery (1.1%), complications were neither frequent nor serious. The median of survival after radical resection is 26 months. CONCLUSIONS: Neo-adjuvant chemotherapy by modern cytostatics is usually well tolerated and creates satisfactory conditions for successful complete resection. The operation proper may be more difficult but need not be associated with serious complications. By this treatment it is probably possible to influence long-term results not only in stage IIIA but to reduce also the risk of a later more remote metastatic dissemination in some patients operated in lower stages of lung cancer. Our present aim is to test parameters which will be able to predict possible failure of induction therapy, and seek factors predicting risk behaviour of the tumour also in lower stages (stage I and II TNM classification).

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Platelet inhibition reduces cyclic flow variations and neointimal proliferation in normal and hypercholesterolemic-atherosclerotic canine coronary arteries.

BACKGROUND: Platelet-derived growth factors help stimulate the neointimal proliferation of restenosis after coronary interventions. Reducing platelet accumulation at treated sites may attenuate restenosis. We tested this hypothesis by inducing repetitive platelet aggregation at coronary angioplasty sites in dogs and measuring subsequent neointima formation. METHODS AND RESULTS: Cholesterol-sensitive dogs (n=74) received either 4% cholesterol-enriched diets for >8 months (n=29), creating visible atheromas, or normal canine diets (n=45). A coronary balloon angioplasty cyclic flow variation (CFV) model was used. One group of control dogs (group 1, n=8) had angioplasty with no arterial constriction applied and no drug treatment. Three other groups had arterial constrictors applied to provoke CFVs: group 2 (n=28) received no drug therapy, group 3 (n=18) received oral aspirin alone, and group 4 (n=20) received 3 oral antiplatelet agents: ridogrel, ketanserin, and clopidogrel (R+K+C) to simultaneously inhibit the thromboxane A(2), serotonin, and ADP pathways of platelet aggregation, respectively. Bleeding times were moderately prolonged in the aspirin-treated group (124+/-9 seconds after 3 weeks versus 76+/-6 seconds at baseline, P<0.01) and greatly prolonged on R+K+C (>600 versus 104+/-5 seconds, P<0.001). The frequency and severity of CFVs were inversely related to the degree of platelet inhibition and prolongation of bleeding times, as was sudden death due to acute thrombotic coronary occlusion. Quantitative histology at 8 weeks revealed increased intima-to-media ratio with CFVs: 0.89+/-0.14 in the untreated group 2 versus 0.11+/-0.04 in the control group (P<0.001). Intima-to-media ratio was significantly reduced with antiplatelet treatment (0.27+/-0.05 with aspirin treatment and 0.20+/-0.05 with R+K+C treatment, respectively, P<0.001). Cholesterol feeding did not appear to influence results. CONCLUSIONS: Repetitive platelet accumulation at coronary angioplasty sites caused enhanced neointimal proliferation by 8 weeks. Oral inhibitors of platelet aggregation attenuated platelet function, prolonged bleeding times, reduced or prevented cyclic flows and abrupt thrombotic occlusions, and thereby inhibited neointimal proliferation. Platelet inhibition should continue to receive attention in efforts to reduce restenosis after coronary interventions.

Administration, Oral↗
PubMed2001

Quantitative assay for group M (subtype A-H) and group O HIV-1 RNA detection in plasma.

A quantitative HIV-1 test is described based on a competitive RT-PCR assay combined with a sandwich hybridization as a detection system. The internal RNA standard (IS) was designed specifically to be competitive during the amplification and during the hybridization step. Sample viral load determination was carried out with one RT-PCR in the presence of 10(3) IS copies. The HIV-1 copy number was calculated by reference to an external standard curve performed on known and increasing amounts of the reference HIV-1 (Ref HIV-1) RNA co-amplified with a constant amount of the IS RNA. The assay had a linear range from 10(1) to 10(6) HIV-1 copies. HIV-1 strains belonging to the different subtypes from group M, but also group O, were all detected. Absolute quantification of purified HIV-1 RNA copies gave identical results as the AMPLICOR HIV-1 Monitor assay. The quantification of patient's samples was evaluated according to different criteria such as dynamic range, sensitivity, efficacy of material recovery, reproducibility and convenience of sample handling. The microplate format of the assay combined with the colorimetric detection provides a convenient tool and fulfills the requirement for routine molecular diagnostic laboratories.

HIV Infections↗
PubMed2001

Effect of cyclosporin A on DNA repair and cancer incidence in kidney transplant recipients.

Cancer incidence is enhanced in transplant recipients. Decreased DNA repair ability is associated with increased cancer incidence. Transplanted patients with cancer were found to have reduced DNA repair. We hypothesized that immunosuppressive therapy may impair DNA repair and thus contribute to the increased cancer incidence in transplanted patients. The objectives of this study were (1) to investigate the effect of two immunosuppressive treatment protocols on DNA repair in kidney transplant recipients; (2) to evaluate the cancer incidence in these patients; and (3) to study the in vitro effect of cyclosporin A (CsA), azathioprine, and prednisolone-separately and in various combinations-on DNA repair. Three groups were studied: (1) a control group; (2) patients treated with azathioprine and prednisone (double-therapy group); and (3) patients treated with CsA, azathioprine, and prednisone (triple-therapy group). The two patient groups did not differ in age, gender, time on dialysis before transplantation, or kidney function or in the number of acute rejections. However, the interval from transplantation to the DNA repair study was shorter in the triple-therapy group (P <.01). DNA repair was induced in peripheral blood mononuclear cells (PBMCs) by ultraviolet irradiation and expressed as tritiated thymidine uptake by these cells. DNA repair in the triple-therapy group was 679 +/- 64 cpm/10(6) cells, significantly less than that in the control group (1049 +/- 69 cpm/10(6) cells, P <.02). In the double-therapy group, DNA repair was similar to that in the control group. The follow-up period was shorter in the triple-therapy group (116 +/- 19 months vs 174 +/- 29 months, P <.01). Five tumors developed in the triple-therapy group, but only one developed in the double-therapy group (P =.05). The in vitro study showed a dose-dependent reduction in PBMC DNA repair by CsA. Azathioprine and prednisolone reduced DNA repair slightly, but CsA reduced DNA repair significantly more than either one or a combination of them. In summary, triple therapy was associated with impaired PBMC DNA repair and increased cancer incidence. CsA was responsible in large part for the reduction in DNA repair ability found in the in vitro and in vivo studies. This may have partly contributed to the enhanced cancer incidence in the kidney transplant recipients.

Adolescent↗
PubMed2001

C. elegans POP-1/TCF functions in a canonical Wnt pathway that controls cell migration and in a noncanonical Wnt pathway that controls cell polarity.

In Caenorhabditis elegans, Wnt signaling pathways are important in controlling cell polarity and cell migrations. In the embryo, a novel Wnt pathway functions through a (beta)-catenin homolog, WRM-1, to downregulate the levels of POP-1/Tcf in the posterior daughter of the EMS blastomere. The level of POP-1 is also lower in the posterior daughters of many anteroposterior asymmetric cell divisions during development. I have found that this is the case for of a pair of postembryonic blast cells in the tail. In wild-type animals, the level of POP-1 is lower in the posterior daughters of the two T cells, TL and TR. Furthermore, in lin-44/Wnt mutants, in which the polarities of the T cell divisions are frequently reversed, the level of POP-1 is frequently lower in the anterior daughters of the T cells. I have used a novel RNA-mediated interference technique to interfere specifically with pop-1 zygotic function and have determined that pop-1 is required for wild-type T cell polarity. Surprisingly, none of the three C. elegans (beta)-catenin homologs appeared to function with POP-1 to control T cell polarity. Wnt signaling by EGL-20/Wnt controls the migration of the descendants of the QL neuroblast by regulating the expression the Hox gene mab-5. Interfering with pop-1 zygotic function caused defects in the migration of the QL descendants that mimicked the defects in egl-20/Wnt mutants and blocked the expression of mab-5. This suggests that POP-1 functions in the canonical Wnt pathway to control QL descendant migration and in novel Wnt pathways to control EMS and T cell polarities.

Animals↗
PubMed2001

Hepatitis C infection in dialysis patients in Israel.

BACKGROUND: Hepatitis C virus is the major cause of acute and chronic hepatitis in patients with end-stage renal disease receiving replacement therapy. OBJECTIVES: To define the prevalence of HCV RNA in a population of patients on dialysis in Israel, to determine the relative risk of acquiring HCV infection while treated by hemodialysis or chronic ambulatory peritoneal dialysis, and to define the HCV genotypes in this population. METHODS: During 1995 we studied 162 dialysis patients. Information was obtained regarding the mode of dialysis, years of treatment, number of blood transfusions, and results of serological testing for HCV, hepatitis B virus, and human immunodeficiency virus. Anti-HCV antibodies were tested by a third-generation microparticle enzyme immunoassay. HCV RNA was determined by polymerase chain reaction. HCV genotyping was performed by a hybridization assay. RESULTS: HCV RNA was detected in 18% of the HD group and 7% of the CAPD group. The number of HCV RNA-positive patients was significantly higher in the HD than the CAPD group (P < 0.05). HCV RNA-positive HD patients were treated longer than the HCV RNA-negative patients (P < 0.02). CONCLUSIONS: Third-generation immunoassay proved to be highly sensitive (94%) and specific (91%) in identifying HCV RNA positivity. Several HCV subtypes were detected, 1b being the most frequent. Identification and isolation of infected HCV patients may minimize its spread in dialysis units and prevent cross-infection.

Adult↗
PubMed2000

Sources on the anterior and posterior banks of the central sulcus identified from magnetic somatosensory evoked responses using multistart spatio-temporal localization.

A Multi-Start Spatio-Temporal (MSST) multidipole localization algorithm was used to study sources on the anterior and posterior banks of the central sulcus localized from early somatosensory magnetoencephalography (MEG) responses. Electrical stimulation was applied to the right and left median nerves of 8 normal subjects. Two sources, one on the anterior and one on the posterior bank of the central sulcus, were localized from 16 data sets (8 subjects, 2 hemispheres). Compared with the more traditional practice of single-dipole fits to peak latencies, MSST provided more reliable source locations. The temporal dynamics of the anterior and posterior central sulcus sources, obtained using MSST, showed considerable temporal overlap. In some cases, the two sources appeared synchronous. On the other hand, in the traditional single-dipole peak-latency fit approach, there is no time course other than a focal dipole moment activated only at the selected peak latency. The same group of subjects also performed a motor task involving index-finger lifting; the anterior central sulcus source obtained from electrical median nerve stimulation localized to the same or similar region in the primary motor area identified from the finger-lift task. The physiological significance of the anterior central sulcus source is discussed. The findings suggest that one can test the integrity of cortical tissue in the region of primary motor cortex using electrical somatosensory stimulation.

Adult↗
PubMed2000

High-Resolution Absorption Spectroscopy of the 3nu(1) and 3nu(1) + nu(3) Bands of Propyne.

The 3nu(1) and 3nu(1) + nu(3) bands of propyne have been recorded at Doppler-limited resolution by Fourier transform spectroscopy and intracavity laser absorption spectroscopy, respectively. The two bands show a mostly unperturbed J rotational structure for each individual K subband. However, as a rule the K structure ordering is perturbed in overtone transitions of propyne and different effective parameters associated with each K subband have been determined. From the vibrational energy levels, a value of -6.6 cm(-1) has been obtained for the x(13) cross anharmonicity in perfect agreement with the origins of the nu(1) + nu(3) and 2nu(1) + nu(3) combination bands estimated from the FTIR spectrum. Hot bands from the v(9) = 1 and v(10) = 1 levels associated with the 3nu(1) + nu(3) combination band have been partly rotationally analyzed and the retrieved values of x(39) and x(3,10) are in good agreement with literature values. Finally, the 4nu(1) + nu(9) - nu(9) band centered at 12 636.6 cm(-1) has been recorded by ICLAS. The red shift of this hot band relative to 4nu(1) and the DeltaB(v) value are discussed in relation to the anharmonic interaction between the 4nu(1) and 3nu(1) + nu(3) + nu(5) levels. Copyright 2000 Academic Press.

Journal Article↗