Biomedical subjects
Publications and source records attributed to S Kremer.
A 61-year-old female presented with a tumor of her left superior orbital rim, which caused blepharoptosis and slight displacement of the globe. X-ray films showed a lytic defect in the frontal bone, while a computed tomography revealed the tumor to extend along the orbital roof, as well as to involve the posterior lamina of the frontal bone. A biopsy taken from the tumor showed it to be an intraosseus cavernous hemangioma.
Fracture of the penis is a relatively rare but significant injury. In the past, it has been treated conservatively with only fair results. There is an increased incidence of complications as well as a prolonged hospital stay with conservative treatment. In this article, we present two instances of fracture of the penis with a review of the literature.
In the human breast carcinoma cell line MDA-468 addition of epidermal growth factor (EGF) is growth inhibitory. Calcium signalling was investigated in this cell line using the calcium sensitive fluorescent probe Indo-1. Addition of EGF to MDA-468 cells resulted in a novel biphasic calcium response. In the first phase of the response EGF raised calcium to levels significantly above basal. This was followed by a prolonged fall in calcium to levels significantly lower than original basal levels. The G-protein activator aluminum fluoride (AlF), stimulated a rise in calcium which was not proceeded by a fall below basal levels. Conversely addition of PMA, an activator of protein kinase C (PKC), induced a fall in calcium from basal without a prior increase. Down regulation of PKC eliminated the response to PMA, however the biphasic nature of the EGF response was maintained. Pretreatment of the cells with pertussis toxin did not alter the response to EGF nor to AlF. We conclude that in the MDA-468 cell in which EGF is growth inhibitory: 1) EGF results in a biphasic calcium response which ultimately leads to reduction below baseline levels, 2) a rise in calcium itself is not sufficient to account for the subsequent fall below basal levels, 3) G-proteins may be involved in the initial phase of the EGF response, 4) activation of PKC can also reduce intracellular calcium, however the response to EGF is not dependent on this pathway.
A method of ossiculoplasty, in cases where the long process of the incus is eroded, is described. The defect created by the erosion of the incus is bridged by an autogenic or allogenic bone graft that leans on the stapes, the remaining part of the incus, and the side of the malleus. These three contact points allow for stability of the bony graft and account for the name tripod. The method was applied in 30 ears and was successful in all but three cases. All the rest (ie, 27 ears) achieved an average gain of 24.8 dB, leaving an average air-bone gap of 11.1 dB. The postoperative air-bone gap was 20 dB or less in all 27 ears that were successfully operated on; and in 21 of them (77.8%), it was no more than 10 dB. The average period of follow-up was 23.8 months. Operative success depended on both the technique chosen and the favorable selection of cases.
The extent of mastoid pneumatization in 150 otosclerotic ears was compared with that of 150 healthy control ears. The size of mastoid pneumatization was measured by use of the Schüller lateral x-ray projection with the help of computed planimetry. The measurements showed the average pneumatized area in otosclerotic ears to be 17.4 +/- 5 cm2, in contrast to 12.9 +/- 4 cm2 for the healthy control ears. The difference between the two groups was highly significant (p less than .0001). While both groups showed a bell-shaped distribution of the measured pneumatized area, the curve of the otosclerotic ears was shifted significantly to the right. Our findings indicate a link between otosclerosis on the one hand and highly pneumatized mastoids on the other. This link between a hereditary disease and a specific type of pneumatization points to the likelihood that heredity also plays some role in determining the final type of pneumatization.
Nephrotoxicity is the major limiting factor in the clinical use of cyclosporine A (CyA), which in its acute form results in a decrease in renal blood flow and glomerular filtration rate. Contractile mesangial cells regulate glomerular capillary patency in response to vasoactive stimuli including vasopressin. Hence the effects of CyA on the cellular signalling mechanism of vasopressin in cultured glomerular mesangial cells were investigated. Vasopressin induced a transient rise in intracellular calcium which was enhanced in the presence of CyA. In addition, CyA decreased both basal and vasopressin stimulated PGE2 production. This inhibition was mediated at least in part at the level of arachidonate release and may involve inhibition of phospholipase A2. We conclude that the increased renal and systemic vasoconstriction that occurs with CyA treatment may be the result of an exaggerated rise in intracellular calcium combined with diminished production of vasorelaxant prostaglandins in response to vasoconstrictor hormones.
Receptors for atrial natriuretic peptide (ANP) have been demonstrated in renal mesangial cells as well as other cell types in the glomerulus. The biochemical basis for the effects of ANP on glomerular hemodynamics remains undefined. Using cultured rat glomerular mesangial cells, we demonstrated a concentration-dependent stimulation of cGMP production in intact cells, and of guanylate cyclase in membranes. Despite the presence of a guanylate cyclase response, ANP had no inhibitory effect on basal inositol trisphosphate production nor on basal cytosolic calcium. Arginine vasopressin stimulated IP3 production, caused a rise in cytosolic calcium as measured using the calcium-sensitive fluorescent probe Indo-1, and caused mesangial cell contraction. ANP caused a slight but significant enhancement of vasopressin-stimulated IP3 production, but had no effect on the cytosolic calcium response nor on the contractile response. 8-Bromo-cGMP likewise had no effect on the generation of the calcium signal. These results indicate that the effects of ANP on glomerular hemodynamics are not mediated by an alteration in the generation of the calcium signal in mesangial cells. In contrast, addition of calcium inhibited ANP stimulated guanylate cyclase activity.
Bradykinin elicits a complex response in the renal glomerulus which includes a reduction in the glomerular capillary ultrafiltration coefficient. To elucidate the biochemical mechanism of this response, we investigated calcium signalling in rat renal glomerular mesangial cells in culture using the calcium-sensitive fluorescent dye, Indo-1. Bradykinin was found to cause a concentration-dependent transient rise in cytosolic free calcium followed by a sustained slower secondary rise. The bradykinin response persisted with acute removal of extracellular calcium using EGTA, indicating that calcium entry from outside the cell did not mediate this primary response. Prolonged exposure to EGTA, which reduced intracellular stores, eliminated the calcium response to bradykinin but not to vasopressin, indicating differential sensitivity to intracellular calcium stores of these two hormonal responses. In agreement, prior stimulation with vasopressin significantly attenuated the response to bradykinin, but the converse did not occur. Aluminum fluoride and pertussis toxin were used to investigate the possible involvement of a guanyl nucleotide regulatory protein in signal transduction. Aluminum fluoride induced a transient rise in cytosolic calcium that was abrogated by prior exposure of the cells to pertussis toxin. This demonstrates the effectiveness of pertussis toxin and the presence of a calcium-signalling pathway susceptible to pertussis toxin in these cells. In contrast, the responses to bradykinin and vasopressin were unaffected by pertussis toxin. We conclude that bradykinin stimulates release of calcium from intracellular stores in glomerular mesangial cells via a pertussis toxin insensitive pathway. This mesangial response provides a direct biochemical basis for the bradykinin-induced fall in glomerular capillary ultrafiltration coefficient which has been observed in vivo.
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This report deals with the clinical and morphological findings in a rare case of Echinococcus granulosus of the female genital tract. The symptoms are not characteristic. A preoperative diagnosis can only be suspected on serological grounds. The diagnosis is confirmed by histological examination of the specimen. The therapy of choice is the surgical removal of the cyst. Care should be taken not to open the cyst during operation. The success of the operation should be confirmed by postoperative serological, ultrasonic, scintigraphic and x-ray controls.
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Cultures of the basidiomycete Mycena avenacea TA 8480 were shown to metabolize pentachlorophenol (PCP), 2,3,5,6-tetrachloro-p-hydroquinone (TeCHQ), and 2,3,5,6-tetrachloro-p-benzoquinone (TeCBQ). The first metabolite of the PCP degradation pathway was identified as TeCBQ which in a second reaction is reduced to the hydroquinone TeCHQ. Subsequently dechlorination of TeCHQ yielded 3,5,6-trichloro-2-hydroxy-p-benzoquinone (TCOHBQ). The specific degradation rate for PCP was 1.4 mg x g dry mycelia -1 x day-1. The initial dechlorination rate of TeCHQ was 5.9 mg x g dry mycelia-1 x hour-1. None of the compounds supported growth of the fungus.
A multilaboratory study was conducted to compare the automated BAX system and the standard cultural methods for detection of Listeria monocytogenes in foods. Six food types (frankfurters, soft cheese, smoked salmon, raw, ground beef, fresh radishes, and frozen peas) were analyzed by each method. For each food type, 3 inoculation levels were tested: high (average of 2 CFU/g), low (average of 0.2 CFU/g) and uninoculated controls. A total of 25 laboratories representing government and industry participated. Of the 2335 samples analyzed, 1109 were positive by the BAX system and 1115 were positive by the standard method. A Chi square analysis of each of the 6 food types, at the 3 inoculation levels tested, was performed. For all foods, except radishes, the BAX system performed as well as or better than the standard reference methods based on the Chi square results.