Search PubMed⌕ Search

Biomedical subjects

J Schreiber

Publications and source records attributed to J Schreiber.

At least 73 records · Page 4Linked to original sources
PubMed1994

Ultrasonography for evaluation of the carotid artery in head and neck cancer.

The dynamic relationship of lymph node metastases to surrounding vascular structures in the neck is important for preoperative patient assessment. When carotid artery involvement is suspected, this relationship often determines whether or not to operate. In the case of adhesive neck metastases along the internal jugular vein, it becomes possible to predict preoperatively if the integrity of this vein may be preserved. Ultrasonography has the ability to differentiate subtle from gross adherence, or simple compression from vascular invasion. This is done by manually palpating the tumor mass and asking the patient to perform various maneuvers while observing on a monitor the relationship of the tumor mass to the nearby artery. This article correlates the preoperative computed tomography/magnetic resonance imaging (CT/MRI) and ultrasound findings in 41 patients with large nodal metastases which were subsequently confirmed during surgery. In case of positive ultrasonographic invasion of the carotid artery, a transcranial Doppler ultrasonography (TCD) exam was performed to confirm adequate crossflow. Our experience with ultrasonography and TCD in patients with suspected involvement of the carotid artery shows reliable results and obviates in our hands the routine need for more complex, invasive, and expensive tests.

Carotid Arteries↗
PubMed1993

[Color duplex ultrasound measurement of lymph node perfusion: a contribution to diagnosis of cervical metastasis].

The objective of this study was to find additional sonomorphological criteria for determining the status of enlarged lymph nodes. By using colour-coded duplex sonography the perfusion of 63 lymph nodes in the neck was analysed. The status was confirmed either histologically or clinically (29 metastases from squamous cell carcinomas and 34 acute or chronic inflammatory nodal diseases). A quantitative evaluation of the pulsatility measured in 51 lymph nodes by computing the Pourcelot-Ratio and the Mean Pulsatility Index yielded significant differences between the two groups. By definition of a limiting value of the Pourcelot-Ratio (0.75) for the prediction of benignity, the specificity and the accuracy in screening for metastases were improved as compared to clinical examination and B-mode sonography. Additional criteria of dignity were found by qualitative evaluation of nodal perfusion patterns (presence and distribution of perfusion, partial loss of perfusion). The use of colour-coded duplex sonography in nodal disease of the neck provides an improvement of early and noninvasive diagnosis of regional metastatic involvement.

Blood Flow Velocity↗
PubMed1992

Ultrasonography for the diagnosis of Lyme disease in cases of acute facial paralysis.

Ultrasonography of the parotid gland was introduced in 1989 as part of the diagnostic protocol of every patient treated in our clinics with acute facial paralysis. Ten of 50 patients so tested were found to have unilateral nonpalpable enlarged lymph nodes in the caudal portion of the parotid gland around the stylomastoid foramen. All 10 patients were eventually diagnosed as having Lyme disease. It is suggested that in patients with acute facial paralysis, ultrasonography is an inexpensive tool to improve diagnosis of Lyme disease and may have a more useful purpose in monitoring therapy.

Acute Disease↗
PubMed1992

Surgical diseases of the falciform ligament.

Surgical lesions of the falciform ligament are rare. Clinically, they present most often as a cystic abdominal mass, and less often as an abscess. Two cases of falciform ligament lesions are reported. The literature, histology, anatomy, clinical manifestations, and surgical management are detailed. Computerized axial tomography (CAT scan) is an essential tool in arriving at a correct preoperative diagnosis. Complete excision of the lesion is curative.

Abscess↗
PubMed1992

Lengthening the human mandible by gradual distraction.

Lengthening of the mandible by gradual distraction was performed on four young patients (average age 78 months). The amount of mandibular bone lengthening ranged from 18 to 24 mm; one patient with Nager's syndrome underwent bilateral mandibular expansion. Following the period of expansion, the patients were maintained in external fixation for an average of 9 weeks to allow ossification. The patients were followed for a minimum of 11 months to a maximum of 20 months with clinical and dental examinations as well as photographic and radiographic documentation. The technique holds promise for early reconstruction of craniofacial skeletal defects without the need for bone grafts, blood transfusion, or intermaxillary fixation.

Bone Lengthening↗
PubMed1991

Acute cutaneous vasculitis associated with prolonged intravenous ritodrine hydrochloride therapy.

A patient with twin gestation was hospitalized because of preterm labor and treated with intravenous ritodrine hydrochloride (Yutopar, Astra Pharmaceutical Products, Westborough, Mass.). After greater than 4 weeks of therapy, the patient had a petechial rash and prolonged bleeding time, which were diagnosed and confirmed by skin biopsy at cesarean section as vasculitis. This is the first documented case of vasculitis associated with ritodrine use.

Adult↗
PubMed1991

Transvaginal intratubal insemination by tactile sensation: a preliminary report.

Transvaginal catheterization of the fallopian tube has gained increased popularity for transfer of embryos and gametes. Forty-five ITIs were performed on 32 patients using the novel approach of tubal transfer via tactile sensation. This group of patients had undergone an average of 5.2 IUIs before ITI. There were a total of 11 pregnancies, 6 occurring with hMG stimulation and 5 with CC-stimulated cycles (34% PR per patient). Three pregnancies ended with spontaneous abortion, and one patient developed acute salpingitis necessitating laparotomy. These data suggest ITI may be effective in assisted reproduction but, as other invasive procedures, is not without risk.

Adult↗
PubMed1991

Electrical field stimulation of isolated guinea pig lung parenchyma strips: a method to study peripheral bronchi and peripheral blood vessels.

The reaction of isolated guinea pig lung parenchyma strips to electrical field stimulation (EFS) has been characterized in vitro. Lung parenchyma strips reacted to EFS with a frequency-dependent initial twitch followed by a long-lasting contraction. The initial fast contraction was abolished by tetrodotoxin, whereas the tonic contraction was not influenced by this substance. The initial twitch was reduced but not abolished by atropine as well as by phentolamine. It was concluded that the reaction of guinea pig lung parenchyma strips to EFS consists of a cholinergic and an adrenergic component representing probably the responses of small bronchi and small blood vessels, respectively. The nature of the nonadrenergic-noncholinergic component of the initial twitch as well as of the nature of the nonneural tonic contraction are still unclear.

Animals↗
PubMed1990

Influence of capsaicin on the reagibility of the isolated guinea pig trachea.

Capsaicin induced a concentration dependent contraction of isolated guinea pig tracheal spirals but did not reduce the tone of submaximally precontracted preparations neither per se nor after pretreatment with a tachykinin antagonist. The contractile reactions to capsaicin did not differ significantly between tracheal preparations obtained from sensitized and nonsensitized animals. A single application of capsaicin (10(-5) M for 15 min) induced a strong contraction of the preparations followed by complete tachyphylaxis to further applications of capsaicin. Such pretreatment with capsaicin did not influence the reagibility of isolated guinea pig tracheas to acetylcholine added exogenously but reduced the allergic contractions of preparations obtained from actively sensitized animals significantly. It is suggested that neuropeptides (e.g. substance P) might be involved in the allergic bronchoconstriction in vitro.

Animals↗
PubMed1990

Effects of ketotifen and clenbuterol on beta-adrenergic receptor functions of lymphocytes and on plasma TXB-2 levels of asthmatic patients.

Clinical observations indicate that beta-adrenergic drugs may increase bronchial reactivity in asthmatics. To find out possible reasons for this phenomenon the beta-adrenergic receptor function of isolated lymphocytes of asthmatic patients treated with clenbuterol alone or with ketotifen and clenbuterol together were studied. The cAMP levels of lymphocytes stimulated by different doses of isoproterenol were measured by radioimmunoassay and have been compared in the groups of healthies, and asthmatic patients after 3-months running of clenbuterol (Spiropent, Sandoz), as well as in the same asthmatics after one-week running of parallel administration of ketotifen and clenbuterol. There was no difference between the beta-adrenergic receptor function in asthmatic patients treated with clenbuterol alone vs. untreated healthies. Applying ketotifen and clenbuterol together the beta-adrenergic receptor function increased compared to the values obtained after application of clenbuterol alone (intraindividual-control) as well as vs. the group of healthies (control). Data presented support the view that therapeutic doses of selective beta 2-agonists do not lead to damage of the beta-adrenoceptor function. The improvement of receptor function after parallel administration of clenbuterol and ketotifen may be a consequence of the participation of ketotifen in the control of beta-adrenergic receptor system. Thus it seems unlikely that down-regulation of beta-adrenergic receptors is responsible for the beta-agonist induced bronchial hyperreactivity. That's why TXB-2 levels in the plasma of the same asthmatic patients and healthy volunteers were determined by RIA.(ABSTRACT TRUNCATED AT 250 WORDS)

Asthma↗
PubMed1989

Detection of glutathione thiyl free radical catalyzed by prostaglandin H synthase present in keratinocytes. Study of co-oxidation in a cellular system.

We report here the application of the electron spin resonance technique to detect free radicals formed by the hydroperoxidase activity of prostaglandin H synthase in cells. Studies were done using keratinocytes obtained from hairless mice. These cells can be prepared in large number and possess significant prostaglandin H synthase activity. Initial attempts to directly detect free radical metabolites of several amines in cells were unsuccessful. A technique was developed based on the ability of some free radicals formed by prostaglandin hydroperoxidase to oxidize reduced glutathione (GSH) to a thiyl radical, which was trapped by 5,5-dimethyl-1-pyrroline N-oxide (DMPO). Phenol and aminopyrine are excellent hydroperoxidase substrates for this purpose and thus were used for all further experiments. Using this approach we detected the DMPO/GS.thiyl radical adduct catalyzed by cellular prostaglandin hydroperoxidase. The formation of the radical was dependent on the addition of substrate, inhibited by indomethacin, and supported by either exogenous arachidonic acid or endogenous arachidonic acid released from phospholipid stores by Ca2+ ionophore A-23187. The addition of GSH significantly increased the intracellular GSH concentration and concomitantly stimulated the formation of the DMPO/GS.thiyl radical adduct. Phenol, but not aminopyrine, enhanced thiyl radical adduct formation and prostaglandin formation with keratinocytes while both cofactors were equally effective in incubations containing microsomes prepared from keratinocytes. These results suggest that prostaglandin hydroperoxidase-dependent co-oxidation of chemicals can result in the intracellular formation of free radical metabolites.

Aminopyrine↗
PubMed1989

Synthesis and characterization of steroid-linked N-(2-chloroethyl)nitrosoureas.

Syntheses of steroid-linked N-[N'-(2-chloroethyl)-N'-nitrosocarbamoyl]-(CNC-) amino acid esters and -amides with potential antineoplastic activity are described. The esters are prepared by reaction of CNC-amino acids with steroids using N,N'-carbonyldiimidazole and N,N'-dicyclohexylcarbodiimide. The corresponding amides are prepared by reaction of 1-(CNC-amino acyloxy)-pyrrolidine-2,5-diones with 17 beta-amino-3-hydroxy-1,3,5(10)-estratriene or 17 beta-O-[4-(6-aminohexylamino)-1,4-dioxo-butyl]-estradiol. Estradiol-17 beta-hemisuccinate is esterified with N-(2-hydroxyethyl)-N'-(2-chloro-ethyl)-N'-nitrosourea (HECNU). Spectroscopic characteristics and relative binding affinities to steroid receptors are given.

Antineoplastic Agents↗