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Biomedical subjects

M Kraus

Publications and source records attributed to M Kraus.

At least 55 records · Page 3Linked to original sources
PubMed2000

A national survey of training in substance use disorders in residency programs.

OBJECTIVE: To determine the amount of formal training in substance use disorders that occurs in selected residency programs and to identify the perceived barriers to such training. METHOD: A national survey was conducted of program directors in emergency medicine, family medicine, internal medicine, obstetrics/gynecology, osteopathic medicine, pediatrics and psychiatry. In 1997, program directors were mailed a brief survey to determine the extent to which required training in substance use disorders occurred and the median number of hours devoted to substance use disorders training. Follow-up telephone surveys were conducted with faculty designated in the survey as responsible for substance-related disorders training to determine type of training and barriers to training. RESULTS: Of 1,831 program directors, 1,183 (64.6%) responded to the brief survey. The percentage of programs with required substance use disorders training ranged from 31.8% in pediatrics to 95.0% in psychiatry, with 56.3% for all programs combined. The median number of curricular hours ranged from 3 (emergency medicine and OB/GYN) to 12 (family medicine). Time was perceived to be the most common barrier to additional training. CONCLUSIONS: Consistent training for all residents in the initial diagnosis and management of substance use disorders has not been achieved. New strategies that integrate into existing residency structures are needed to improve substance use disorders training. Faculty development in substance use disorders and review of current substance use disorders training as part of the residency review process should facilitate this endeavor.

Alcoholism↗
PubMed1999

Influence of NOS inhibitors on changes in ACH release and NO level in the brain elicited by amphetamine neurotoxicity.

We studied the possible role of neurotoxicity in the d,l-amphetamine (AMPH)-induced release of acetylcholine (ACH) in the nucleus accumbens (Nac) and the involvement of endogenous NO in this process. For determination of ACH release the Nac was superfused using the push-pull-technique. NO was directly measured using the electron paramagnetic resonance technique. Repeated administration of AMPH increased ACH release by about 400%. N-nitro-L-arginine (L-NNA) and 7-nitroindazole (7-NI) nearly abolished the AMPH-induced increase in ACH release. AMPH increased NO as well as lipid peroxidation (LPO) products in the cortex. L-NNA and 7-NI substantially diminished NO increase. AMPH-evoked LPO was only slightly reduced by these compounds. It is concluded that AMPH enhances ACH release through increased NO synthesis and induces neurotoxicity via NO and by LPO independent NO generation.

Acetylcholine↗
PubMed1999

Otogenic lateral sinus thrombosis in children.

INTRODUCTION: The clinical picture of lateral sinus thrombosis (LST) has changed with the advent of antibiotics, as have the utility of various diagnostic tests. LST may appear in children as a complication of acute otitis media, but nowadays it is more frequently encountered in adults with long-standing chronic ear disease. METHOD: A retrospective study of all the pediatric patients with LST between 1982 and 1997. RESULTS: Thirteen cases of LST were diagnosed and treated by our department. In six cases, LST was due to acute otitis media and in the remaining cases it was due to chronic otitis media. Headache, fever, aural discharge and mastoid tenderness were the most frequent findings in these patients and four patients were initially diagnosed with meningitis. In the majority of the patients, LST was accompanied with other intracranial complications, such as perisinus abscess, brain abscess and meningitis. One patient with multiple brain abscesses, unresponsive to several drainage procedures, died. The other patients recovered and have since been followed-up as out-patients. CONCLUSION: LST may be difficult to diagnose due to previous antibiotic treatment and to the overlap of clinical findings with other entities such as meningitis. Despite the value of modern imaging techniques in the investigation of the disease, a high index of suspicion based on the clinical picture is warranted. Our results are consistent with those of other recent studies, who found that mortality of LST has dropped below 10%.

Acute Disease↗
PubMed1999

Synthesis and secretion of the anticoagulant protein S and coexpression of the Tyro3 receptor in human lung carcinoma cells.

BACKGROUND: Protein S is a plasma protein that serves as an important cofactor for activated protein C in the blood anticoagulation system. Protein S also acts as a mitogen on distinct cell types and is a ligand for Tyro3, a member of the Axl family of oncogenic receptor tyrosine kinases. This lends support to the hypothesis that protein S might also be involved in tumor cell regulation. METHODS: The expression of protein S and receptor Tyro3 was examined in 22 lung carcinoma cell lines and normal bronchial epithelial cells by reverse transcriptase-polymerase chain reaction. Secreted protein S was identified by Western blot analysis of cell supernatants and tested in a protein S-dependent clotting test for anticoagulant activity. Immunohistochemistry with anti-protein S polyvalent antiserum was also performed on 31 primary lung carcinoma specimens. RESULTS: Protein S mRNA and secreted protein were found in 11 of 12 cell lines of nonsmall cell lung carcinoma (NSCLC) origin and in normal bronchial epithelial cells, but they were found in only 4 of 10 small cell lung carcinoma (SCLC) cell lines. The majority of lung carcinoma cell lines that expressed protein S (13 of 15) also revealed expression of the cognate receptor, Tyro3. Protein S that was present in cell supernatant had anticoagulant activity comparable to that of plasma protein S, suggesting that it is gamma-carboxylated. In lung tumor tissue, protein S antigen was found in 20 of 31 cases examined, predominantly in tumors of the squamous cell and bronchioalveolar cell types. Protein S was found not only in tumor cells but also in cells of the normal bronchial epithelium, in alveolar macrophages, and in endothelium. CONCLUSIONS: To the authors' knowledge, their report is the first of the synthesis of an active anticoagulant protein in epithelial cells of human cancer. It suggests that protein S, by binding to a receptor (Tyro3), may influence local anticoagulation events or other, as yet unidentified, aspects of lung tumor development.

Antigens, Neoplasm↗
PubMed1999

[Indications criteria for total cavopulmonary anastomosis (Fontan operation)].

OBJECTIVES: In a retrospective study we evaluated the predictive value of the traditional risk factors (Fontan criteria) for mortality and morbidity after total cavopulmonary anastomosis (Fontan operation). DESIGN: We studied 51 consecutive patients who underwent Fontan operations from 1982 through 1994. Morbidity was assessed by a score taking equally into account rhythm disturbances, cardiovascular hospital admissions and heart failure. RESULTS: The mean age at operation was 4.1 +/- 3.4 years. Diagnoses were tricuspid atresia in 20, complex single ventricle in 13 and various complex congenital heart defects in 18 patients. All Fontan criteria were fulfilled in 11 patients while in the remaining 40 up to 6 criteria were not met. The criteria least fulfilled were age in 31 patients and pulmonary artery anatomy in 11. The mean follow-up was 4.6 +/- 3.0 years. The overall 30-day survival was 84% and 1- and 10-year survival 76.5% respectively. All patients who fulfilled all the Fontan criteria survived. The overall mortality and early mortality were associated with a significantly higher number of unfulfilled Fontan criteria (p < 0.01). Age below 2 years at operation and pulmonary resistance > 4 Woods units were risk factors for overall mortality (p < 0.01). The number of unmet Fontan criteria was not significantly different in patients with and without postoperative late morbidity. CONCLUSIONS: The Fontan criteria are reliable predictors for mortality but have little predictive value for morbidity. Surviving patients who do not fulfil all criteria suggest that some criteria may need to be modified. Our limited data support a lower age limit of 2 instead of 4 years.

Adolescent↗
PubMed1999

Histaminergic neurons modulate acetylcholine release in the ventral striatum: role of H3 histamine receptors.

To investigate whether histaminergic neurons influence the activity of cholinergic neurons, the ventral striatum was superfused through a push-pull cannula and the release of endogenous acetylcholine was determined in the superfusate. Local inhibition of histamine synthesis by superfusion with alpha-fluoromethylhistidine (FMH) gradually decreased the release rate of acetylcholine. Superfusion with histamine increased the release of acetylcholine. The releasing effect of histamine was greatly inhibited when the striatum was simultaneously superfused with the D2/D3 agonist quinpirole and the D1 antagonist (+/-)-7-bromo-1-(fluoresceinylthioureido)phenyl-8-hydroxy-3-methyl -2,3,4,5-tetrahydro-1H-3-benzapine (SKF 83566). The effect of histamine on acetylcholine release was abolished by the GABA(A) receptor antagonist bicuculline. Superfusion with the H3 receptor agonists imetit or immepip increased acetylcholine release rate in the striatum. The releasing effects of the two H3 agonists were FMH resistant, while superfusion with quinpirole and SKF 83566 abolished the H3 receptor agonist-induced acetylcholine release. Superfusion with the H3 receptor antagonist thioperamide enhanced acetylcholine release rate. The releasing effect of thioperamide was abolished after inhibition of histamine synthesis by FMH. The release of acetylcholine by thioperamide was also abolished on simultaneous superfusion with quinpirole and SKF 83566. The findings show that, in the striatum, the activity of cholinergic neurons is permanently modulated by neighbouring histaminergic nerve terminals and axons. The release of acetylcholine is also permanently inhibited by neighbouring GABAergic neurons. The enhanced release of acetylcholine by the H3 receptor agonists imetit and immepip is due to stimulation of H3 heteroreceptors, while the increase of acetylcholine release by the H3 receptor antagonist thioperamide is elicited via blockade of H3 autoreceptors. Histamine released from histaminergic nerve terminals increases the release of acetylcholine in part by inhibition of dopamine release which, in turn, decreases GABAergic transmission. A dopamine-independent way seems also to be involved in the histamine-evoked acetylcholine release.

Acetylcholine↗
PubMed1999

Histaminergic neurons modulate acetylcholine release in the ventral striatum: role of H1 and H2 histamine receptors.

To investigate whether H1 and H2 histamine receptors are implicated in the modulation of acetylcholine release by endogenous histamine, the ventral striatum of the conscious, freely moving rat was superfused by the push-pull superfusion technique with drugs and the release of acetylcholine was determined in the superfusate. Superfusion with the H1 receptor agonist 2-thiazolylethylamine (TEA, 50 micromol/l) enhanced the release of acetylcholine, while the H1 receptor antagonist triprolidine (50 micromol/l) reduced acetylcholine outflow and abolished the TEA-evoked release of the neurotransmitter. The inhibitory effect of triprolidine was not influenced either on simultaneous superfusion with 10 micromol/l (+/-)-7-bromo-1-(fluoresceinylthioureido)phenyl-8-hydroxy-3-methyl -2,3,4,5-tetrahydro-1H-benzazepine (SKF-83566, D1 dopamine receptor antagonist) and 50 micromol/l quinpirole (D2/D3 dopamine receptor agonist) or on superfusion with the GABAA receptor antagonist bicuculline (50 micromol/l). The H2 receptor antagonists ranitidine or famotidine (50 micromol/l each) greatly enhanced acetylcholine release rate in the ventral striatum. Presuperfusion with alpha-fluoromethylhistidine (FMH, 1 mmol/l), which inhibits neuronal synthesis of histamine, abolished the famotidine-induced release of acetylcholine. The releasing effect of famotidine was also abolished on simultaneous superfusion with 10 micromol/l SKF-83566 and 50 micromol/l quinpirole. The release of acetylcholine elicited by famotidine was reversed to a decreased acetylcholine outflow when the striatum was superfused with the GABA(A) receptor antagonist bicuculline (50 micromol/l) prior to famotidine. Superfusion with the H2 receptor agonist impromidine (1 micromol/l) decreased acetylcholine outflow, while the H2 agonist dimaprit (50 micromol/l) exerted the opposite effect. The releasing effect of dimaprit was not influenced by FMH (1 mmol/l), but it was abolished in the presence of SKF-83566 (10 micromol/l) and quinpirole (50 micromol/l). In the presence of bicuculline the release of acetylcholine by dimaprit was enhanced and prolonged. It seems possible that dimaprit and impromidine stimulate different subtypes of H2 receptors. The findings suggest that the release of acetylcholine in the striatum is modulated by neighbouring histaminergic neurons in a complex way. Stimulation of H1 histamine receptors, probably located on cholinergic neurons, enhances acetylcholine release. Stimulation by histamine of H2 receptors located on cholinergic or GABAergic neurons enhances the release of acetylcholine, while stimulation of H2 receptors located on dopaminergic neurons exerts the opposite effect.

Acetylcholine↗
PubMed1999

[Low energy extracorporeal shockwave therapy (ESWT) for treatment of myogelosis of the masseter muscle].

Patients with functional disorders of the temporomandibular apparatus often show painful myogelosis, especially of the masseter muscle. The cause is hypertonia of the affected muscle. The aim of the presented single-blinded clinical trial was to analyze the effects of low-energy extracorporeal shock waves on patients with pain sensitivity in this region. Participating in the trial were 50 patients with painful, palpable and sonographically evident myogelosis of the masseter muscle. Half of the patients received a single application of 250 impulses of 0.04 mJ/mm2. The second half received an equivalent placebo treatment with the shock-wave impact being inhibited by a neopren insert. It was shown that in 64% of the patients significant alleviation of pain with palpable and sonographically evident softening of the myogelosis could be achieved. In 40% of the patients the therapeutic result could be conserved over a period of 2 weeks. The difference from the placebo group was statistically highly significant. ESWT is thus an easy-to-use, non-invasive method of initial pain therapy for patients with functional disorders. To preserve the long-term therapeutic result, additional functional therapy is nevertheless necessary.

Adult↗
PubMed1999

Trisomy 3 in gastric lymphomas of extranodal marginal zone B-cell (mucosa-associated lymphoid tissue) origin demonstrated by FISH in intact paraffin tissue sections.

Some reports have indicated that trisomy 3 represents a characteristic chromosomal abnormality found in lymphomas arising in mucosa-associated lymphoid tissues (MALT)/extranodal marginal zone B-cells (MZBC). Traditional cytogenetic analysis of metaphase preparations is cumbersome and not always possible, especially in those situations in which the diagnosis in not suspected before a biopsy. Our aim is to use a relatively simple method to evaluate trisomy 3 in paraffin-embedded, formalin-fixed tissue, using fluorescence in situ hybridization (FISH) on intact tissue sections. Formalin-fixed, paraffin-embedded archival tissues from 30 cases (27 lymphoma and 3 chronic gastritis cases) were hybridized with a chromosome 3 specific alpha-satellite probe (ONCOR, Gaithersburg, MD). Three of four cases of gastric MZBC/MALT lymphoma revealed trisomy 3. Ten cases of lymphoma of possible or probable MZBC origin were examined, and four revealed trisomy 3. Five of 13 non-MZBC lymphomas revealed trisomy 3. None of the chronic gastritis cases nor normal tonsil cases revealed trisomy 3. Our results, using a different methodological approach, confirm the findings of others that trisomy 3 is an abnormality found in a significant proportion of lymphomas of MZBC origin. Our approach also makes possible interphase cytogenetic analysis (by FISH) of routinely processed formalin-fixed, paraffin-embedded tissues, without the need to disaggregate cells. It thus may facilitate genetic analysis on specimens previously deemed unsuitable for such analysis, particularly when tissue quantity is limited.

Adult↗
PubMed1999

Randomized comparison of high-flow versus conventional hemodialysis catheters.

PURPOSE: To evaluate short-term flow rates achieved with a new split-tip polyurethane hemodialysis catheter. PATIENTS AND METHODS: This was a prospective, randomized, nonblinded study. Patients referred for a tunneled-dialysis catheter received either a conventional silicone (Bard Hickman 13.5 F) if randomized to the control group, or a split-tip, high-flow polyurethane (MedComp AshSplit 14.5 F) catheter if randomized to the study group. Effective flow rates (QbEff) and recirculation were measured with use of ultrasonic dilution at pump settings (Qb) of 200, 300, 350 and 400 mL/min, as well as maximum Qb (QbMax, up to 500 mL/min) sustainable for at least 3 minutes. Measurements were repeated weekly for 6 weeks. Procedure times and initial and late complications were recorded. RESULTS: Twelve patients were enrolled in each group, 11 and eight completed the study in the test and control groups, respectively. Insertion complications, limited to the split-tip group, included asymptomatic air embolus (n = 1), prolonged tunnel bleeding (n = 2), and kinking (n = 2). Recirculation in both groups was low (mean < 6% at all flow rates). QbMax was 499 mL/min in the Ash group and 470 mL/min in the Hickman group. A repeated measures analysis of variance was used. Adjusted (for week) mean effective flow rates (Qbeff, mL/min) were as follows: at Qb = 200, Ash = 211, Bard = 211, P = .93; at Qb = 300, Ash = 301, Bard = 292, P = .28; at Qb = 350, Ash = 341, Bard = 314, P = .03; at Qb = 400, Ash = 375, Bard = 329, P = .01; at QbMax, Ash = 422, Bard = 359, P = .0005. CONCLUSION: Both catheters delivered flows within the acceptable range indicated by the Dialysis Outcomes Quality Initiative. The split-tip catheter is capable of higher flow rates (Qb and QbEff) compared with the conventional catheter, which may allow more efficient dialysis. Insertion complications appear to be higher with the new design.

Blood Flow Velocity↗
PubMed1999

Ig-alpha cytoplasmic truncation renders immature B cells more sensitive to antigen contact.

To study the function of Ig-alpha in the selection of autoreactive B cells, we have analyzed mb-1 cytoplasmic truncation mutant mice (mb-1delta(c)/delta(c)), which coexpress transgenes encoding hen egg lysozyme (HEL) and HEL-specific immunoglobulin. We demonstrate that in the presence of soluble HEL (sHEL) and dependent on the mb-1delta(c) mutation, most immature B cells bearing the HEL-specific Ig transgene undergo rearrangements of endogenous kappa light chains, resulting in loss of HEL specificity. Moreover, immature B cells from Ig-alpha mutant mice respond to BCR cross-linking with an exaggerated and prolonged calcium response and induction of protein tyrosine phosphorylation. Our data imply a negative signaling role for Ig-alpha in immature B cells.

Animals↗
PubMed1999

Mycobacterial cervical lymphadenitis: the histological features of non-tuberculous mycobacterial infection.

AIMS: The distinction between nontuberculous mycobacterial (NTM) lymphadenitis and other causes of cervical lymphadenitis is critical, as different entities call for different treatments. Despite modern diagnostic techniques for NTM infections their prompt and accurate diagnosis is still difficult. We assessed the value of different histological features in diagnosing clinically suggestive NTM cervical lymphadenitis in cases of granulomatous cervical lymphadenitis. METHODS AND RESULTS: A retrospective study of 30 patients with a clinical diagnosis of NTM cervical lymphadenitis was carried out. The patients were divided into three subgroups and several histological parameters were examined in each subgroup. A comparison was made with cases of proven tuberculous lymphadenitis. Four histological features (presence of microabscesses, ill-defined granulomas, noncaseating granulomas and a small number of giant cells) were found with significant statistical difference when comparison was made between the NTM group and the tuberculosis group. CONCLUSIONS: A rapid and accurate diagnostic procedure for NTM lymphadenitis is not yet available. Therefore, in the presence of a suggestive clinical picture for NTM lymphadenitis, we propose four histological features which support this diagnosis, thus allowing prompt therapeutic intervention.

Adult↗
PubMed1999

Determination of the complete covalent structure of the major glycoform of DQH sperm surface protein, a novel trypsin-resistant boar seminal plasma O-glycoprotein related to pB1 protein.

The complete covalent structure of a novel boar DQH sperm surface protein resistant to many classical procedures of enzymatic fragmentation was determined. The relative molecular mass of the major form of this protein determined by ESI-MS and MALDI-MS was 13,065.2+/-1.0 and 13,065.1, respectively. However, additional peaks differing by 162 Da (i.e., minus hexose), 365 Da (i.e., minus hexose and N-acetylhexosamine), 146 Da (i.e., plus deoxyhexose), and 291 Da (i.e., plus sialic acid) indicated the heterogeneity due to differences in glycosylation. The complete covalent structure of the protein was determined using automated Edman degradation, MALDI-MS, and post-source decay (PSD) MALDI-MS, and shown to consist of N-terminal O-glycosylated peptide followed by two fibronectin type II repeats. The carbohydrates are O-glycosidically linked to threonine 10, as confirmed by PSD MALDI-MS of the isolated N-terminal glycopeptide. Eight cysteine residues of the protein form four disulfide bridges, the positions of which were assigned from MALDI-MS and Edman degradation data. We conclude that mass spectral techniques provide an indispensable tool for the detailed analysis of the covalent structure of proteins, especially those that are refractory to standard approaches of protein chemistry.

Amino Acid Sequence↗
PubMed1999

Characterization of boar spermadhesins by monoclonal and polyclonal antibodies and their role in binding to oocytes.

PROBLEM: The role of Ala-Trp-Asn (AWN) and Ala-Gln-Asn (AQN) families of spermadhesive sperm proteins in fertilization. METHOD OF STUDY: The preparation and characterization of polyclonal antibodies against AWN and AQN spermadhesins and one monoclonal antibody (MAb), designated Bo.5, against AWN spermadhesin. The use of biochemical and immunocytochemical methods for characterization of spermadhesins on the sperm membrane of boar spermatozoa and in the cryostat sections of boar reproductive organs. RESULTS: Polyclonal anti-AWN and anti-AQN antibodies specifically reacted with AWN and AQN proteins, respectively. MAb Bo.5 detected the 17-, 16-, and 14-kDa protein members of AWN subfamily. The monoclonal, as well as the polyclonal, AWN antibodies remarkably decreased the sperm binding to the egg surface in an in vitro sperm zona pellucida binding assay. CONCLUSIONS: Presented results demonstrate that polyclonal antibodies and MAb Bo.5 against spermadhesins specifically recognize the membrane-associated antigens and inhibit the binding of sperm to oocytes. Reduced binding of sperm to oocytes, due to the antibodies, indicates the role of these spermadhesins in sperm-egg primary binding.

Animals↗