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Biomedical subjects

N Marcus

Publications and source records attributed to N Marcus.

At least 19 recordsLinked to original sources

Streptococcus acidominimus infection in a child causing Gradenigo syndrome.

UNLABELLED: Gradenigo syndrome is a rare presentation of acute petrositis. The clinical triad of Gradenigo syndrome consists of acute suppurative otitis media, severe unilateral headache and abducens nerve palsy. We report the first case of Gradenigo syndrome caused by Streptococcus acidominimus, a Gram-positive coccus of the Streptococcus viridans group, which rarely causes deep-seated infection in humans. CONCLUSION: Gradenigo syndrome may complicate acute otitis media and should be suspected in case of unilateral headache and abducens nerve palsy. Conservative medical treatment without surgery may be considered in some patients.

Abducens Nerve Diseases↗

Transient hypoparathyroidism due to amphotericin B-induced hypomagnesemia in a patient with beta-thalassemia.

OBJECTIVE: To report a case of transient hypoparathyroidism that developed in a beta-thalassemic patient due to amphotericin B-induced hypomagnesemia. CASE SIJMMARY: A 21-year-old man with beta-thalassemia was treated with amphotericin B for Candida albicans intravenous line sepsis. After five days of treatment (cumulative dose 160 mg), he developed hypomagnesemia, which caused hypoparathyroidism and hypocalcemia; all three abnormalities resolved after the drug was withdrawn. DISCUSSION: Patients with beta-thalassemia may develop endocrinologic abnormalities due to excessive iron deposition. Some may have subclinical hypoparathyroidism that clinically emerges after even a mild homeostasis disturbance. Amphotericin B is associated with variable adverse effects including renal tubular insult, which may induce hypomagnesemia following relatively short treatment. The resolution of hypomagnesemia, hypocalcemia, and hypoparathyroidism in our patient after discontinuation of amphotericin B treatment suggests that the endocrine dysfunction was due to a drug-related adverse effect and not to parathyroid dysfunction caused by iron deposition. CONCLUSIONS: This case demonstrates a known but rarely reported adverse effect of amphotericin B, namely hypomagnesemia, that may occur even at a low cumulative dose. It also emphasizes that patients with an underlying disease, such as thalassemia, may be more susceptible to hypoparathyroidism and hypocalcemia during treatment with amphotericin B.

Adult↗

Fluid-fluid levels in a simple bone cyst on magnetic resonance imaging.

An unusual case is presented here of simple bone cyst (SBC) with fluid-fluid levels on MR and cementum-like substance on microscopy in an atypical location in the distal femur. Fluid-fluid levels are commonly described in the literature within aneurysmal bone cysts, giant cell tumour, chondroblastomas and telangiectatic osteosarcomas, but a literature review revealed only one reported case with multiple fluid levels occurring in a simple bone cyst on MRI. A cementum-like matrix is diagnostic of SBC and is seen in approximately 10% of cases.

Bone Cysts↗

Rapid increase in the prevalence of antimicrobial drug resistance among enterococcal blood isolates in southern Israel.

A prospective surveillance was conducted to monitor the prevalence and dynamics of antimicrobial resistance among enterococci isolated from blood cultures in southern Israel. A total of 242 organisms isolated between 1993 and 1996 were studied. The prevalence of Enterococcus faecalis significantly decreased during the study period, whereas that of Enterococcus faecium doubled. Antimicrobial drug resistance increased steadily among Enterococcus faecium isolates: resistance to ampicillin increased from 19% in 1993-1994 to 53% in 1995, and to 67% in 1996 (p = 0.005); during the same period, resistance to vancomycin increased from 0% to 20%, and to 50% (p = 0.002), and combined resistance to ampicillin and vancomycin and high-level resistance to gentamicin from 0% to 20% and to 38% (p < 0.02).

Ampicillin Resistance↗

NF-Y, a CCAAT box-binding protein, is one of the trans-acting factors necessary for the response of the murine ERp72 gene to protein traffic.

The accumulation of incompletely assembled immunoglobulin mu heavy chain in transfected COS cells stimulates the cellular response to protein traffic that results in the increased transcription and elevated synthesis of several ER chaperones, including ERP72, a member of the protein disulfide isomerase family of molecular chaperones. The ERp72 promoter contains an 82 bp ER protein traffic response element (ERPTRE) that is sufficient to mediate this response. Previously, it had been shown that the alteration of a putative AP-2 site and a CCAAT and inverted CCAAT site within the ERPTRE significantly decreased the response of ERp72 promoter to mu chain accumulation. We have extended these findings by demonstrating a role for NF-Y and a potentially novel DNA-binding protein in the regulation of transcription from the ERp72 promoter. The fact that NF-Y binding to the ERPTRE is observed in extracts from both control cells and cells in which the response to protein traffic has been activated indicates that the binding of NF-Y, while necessary, is not sufficient to account for the response. Each of the two CCAAT sites in the ERPTRE can bind NF-Y independently, but both sites must be intact for full ERPTRE function. A second protein can bind to the ERPTRE independently of NF-Y and at a site overlapping or close to the 3' end of the reverse CCAAT site. It is possible that interactions between NF-Y, this protein and perhaps other factors are responsible for the regulation of the protein traffic response.

Animals↗

Tissue distribution of three members of the murine protein disulfide isomerase (PDI) family.

The distribution of PDI, ERp61 and ERp72, members of the protein disulfide isomerase (PDI) family of endoplasmic reticulum (ER) proteins, was determined in various murine tissues. Relative amounts of mRNA were measured using a quantitative reverse transcription-polymerase chain reaction (RT-PCR) method. Protein levels were determined from Western blots. In most tissues, protein levels paralleled the amount of mRNA for each PDI family member. The tissue distribution of the PDI and ERp72 mRNAs was similar, although ERp72 was not as abundant as PDI in the tissues. The tissue distribution of the ERp61 mRNA was significantly different from the two other family members. To help define potential hormonal or maturational differences in the regulation of expression of PDI family members, mRNA was measured in the frontal cortex, liver, pituitary gland and uterus at timed intervals during postnatal maturation. Except in the pituitary gland, the mRNA levels at 10 days and 22 days after birth were essentially identical to those in the adult. The ERp61 and ERp72 mRNAs were present at 2- to 3-fold higher levels in the pituitary glands of the 10- and 22-day-old mice, than in the adult mice. In addition, the pituitary gland PDI mRNA was 2- to 3-fold higher in 10-day-old mice than in adults. In general, levels of PDI family members were higher in secretory tissues than in other tissues in both immature and adult mice.

Age Factors↗

Erp61 is GRP58, a stress-inducible luminal endoplasmic reticulum protein, but is devoid of phosphatidylinositide-specific phospholipase C activity.

Using antibody raised against putative Form I phosphatidylinositide-specific phospholipase C (PI-PLC) and direct amino acid sequencing of the protein recognized by this antibody, we have shown that the antibody reacts with luminal endoplasmic reticulum (ER) proteins, including ERp61. ERp61 possesses a COOH-terminal QEDL sequence that acts as an ER retention signal. Additional experiments have shown, however, that PI-PLC activity is separable from ERp61 and that rat or murine ERp61 expressed in COS cells failed to produce an increase in PI-PLC activity in the COS cells. Finally, we have identified ERp61 as GRP58, a 58-kDa protein inducible by glycosylation block and treatment with the Ca2+ ionophore, A23187.

Amino Acid Sequence↗

Distribution of neurons with high-affinity uptake sites for GABA in the myenteric plexus of the guniea-pig, rat and chicken.

The occurrence of neurons possessing high-affinity uptake sites for GABA was studied in the myenteric plexus of the guinea-pig ileum, caecum, and proximal and distal colon, the rat proximal colon, and the chicken gizzard with the use of 3H-GABA and autoradiography. Experiments were carried out on plexuses that had been freshly isolated from the gut wall or on isolated plexuses that had been maintained as explant cultures for 7 to 14 days. Scattered neurons selectively labelled with 3H-GABA were found in the myenteric plexuses from all the areas examined. The results suggest that GABAergic neurons are widely distributed in the enteric nervous system.

Animals↗

Erythrocyte AMP-deaminase: an investigation of the increase in activity during chick maturation.

1. AMP-deaminase activity in erythrocytes increases gradually during chick (Gallus domesticus) maturation, reaching the adult level of enzymatic activity at about 16 weeks after hatching. 2. Adenosine deaminase activity increases approximately two-fold during this period. 3. Substrate specificity and immunoinhibition studies indicate that erythrocytes from adult chickens and newly-hatched chicks contain the same AMP-deaminase isozyme. 4. Comparison of temporal changes in RBC AMP-deaminase with those previously described for this enzyme in muscle and brain suggests that the level of this enzyme is regulated differently in these tissues.

AMP Deaminase↗

Clinical applications of biofeedback: implications for psychiatry.

The authors briefly describe biofeedback techniques such as EMG feedback, temperature feedback, and heart rate feedback, along with reports from the literature about their application to specific problems such as subvocalization while reading, Raynaud's disease, cardiac arrhythmias, and epilepsy. Many clinical applications of biofeedback are aimed at inducing relaxation, a state that has important psychotherapeutic potential. The authors suggest that biofeedback could be used to reduce a patient's general level of arousal or as an adjunct to behavior therapy or insight therapy. While there have been no reports in the literature of any harmful effects secondary to feedback training, the authors caution that some patients may respond negatively to an objectively measured state of relaxation.

Anxiety↗