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Biomedical subjects

G Abrams

Publications and source records attributed to G Abrams.

At least 37 records · Page 2Linked to original sources

MR imaging of pseudotumor cerebri.

Eleven obese young women with idiopathic pseudotumor cerebri were studied with high-field-strength (1.5 T) MR imaging to demonstrate increased water content in the brains of such patients. Heavily T2-weighted studies were obtained for 10 patients, and balanced (long TRs, short TEs, spin density, proton density) pulse sequences were obtained for four patients. We examined the studies of morphologically normal periventricular white matter and developed a white matter water index to determine if a slight increase in signal was present that could be ascribed to low levels of edema. Comparison was made to an age-matched control group. We also examined five patients with sodium MR imaging. Two of the 11 patients had focal areas of increased signal in their periventricular white matter. Presumably, these are areas of increased edema above the background that could not be detected on the CT scan. The white matter water index for the normal controls was an average of 0.479 (+/- 0.015), while that of the pseudotumor cerebri group was 0.520 (+/- 0.016). This indicates an increase in the white matter water signal. We believe this represents a diffuse low level of edema. These findings are consistent with previous estimates of the increase in brain water in patients with idiopathic pseudotumor cerebri. The patients with focally abnormal proton studies demonstrated similar abnormalities on their sodium studies.

Adult↗

Islet cell hyperplasia: an unusual cause of hypoglycemia in an adult.

This is a case presentation of a 32-year-old man with a one year history of symptomatic hypoglycemia and documented elevations of his fasting plasma insulin to glucose ratio, caused by islet cell hyperplasia. Islet cell hyperplasia is a common cause of hypoglycemia in the pediatric population, but is very rare in adults. As in the pediatric group, adults should be treated with subtotal (75-85%) resection of the pancreas and with diazoxide for symptomatic recurrence of hypoglycemia. We suggest that the term islet cell hyperplasia is preferred to designate a diffuse proliferation of endocrine cells that may express itself with different morphologic patterns, varying from case to case. Islet cell hyperplasia, therefore, comprises nesidioblastosis, endocrine cell budding from ductal structures, as well as islet and islet cell hypertrophy, septal islets, islet dysplasia, and adenomatosis. Immunohistochemistry is a valuable method for the demonstration of the polymorphic hormonal content of the proliferated islet cells. We propose that the term nesidioblastosis, previously used to describe some similar cases, should be avoided because of confusion about its definition.

Adult↗

Ototoxicity of cisplatin vs. platinum analogs CBDCA (JM-8) and CHIP (JM-9).

Cis-diamminedichloroplatinum (cisplatin), a divalent platinum compound and cell-cycle nonspecific chemotherapeutic agent, produces a permanent high-frequency sensorineural hearing loss and a dose-related cumulative renal insufficiency with tubular necrosis and interstitial nephritis. Synthetic platinum analogs are presently being tested to identify an analog with greater antitumor activity, but less ototoxicity and nephrotoxicity than cisplatin. The objectives of this study were to analyze the potential cochlear and nephrotoxic effects of two synthetic platinum analogs presently in phases I and II of clinical trials, CBDCA [JM-8 or cis-diammine, 1,1-cyclobutane dicarboxylato (2)-0,0(1)-platinum (NSC-241240)] and CHIP [JM-9 or cis-dichloro-trans-dihydroxybisisopropylamine platinum IV (NSC-256927)]. Cytocochleography, auditory brain-stem evoked response (ABR), double-blind light microscopy of renal tissues, and gamma emission analysis of 195mpt localization in viscera and inner ear were employed in the evaluation of cisplatin and platinum analogs (JM-8 and JM-9) in adult guinea pigs. Final results indicate that the investigational chemotherapeutic analogs CBDCA (JM-8) and CHIP (JM-9) do not produce the ototoxicity and nephrotoxicity characteristic of cisplatin. Furthermore, these findings demonstrate 195mpt localization in the vestibular labyrinth and confirm previous platinum distribution studies in the organ of Corti and stria vascularis tissues.

Animals↗

Ototoxic and nephrotoxic effects of combined treatment with cis-diamminedichloroplatinum and kanamycin in the guinea pig.

Ototoxic and nephrotoxic potentiation with concomitant cis-diamminedichloroplatinum, or cis-platinum II (CSP), and aminoglycoside therapy was investigated in the guinea pig. We evaluated possible potentiation of the toxic effects of CSP and kanamycin compared with CSP alone in the inner ear and kidney and quantitatively localized CSP in the cochlea with gamma emission analysis of 195mPt. Kanamycin-treated animals demonstrated cytocochleograms and ABR waveforms, absolute latencies, and interwave latencies for waves I, II, and III similar to control animals at our maximum level of acoustic stimulation. CSP treatment produced 60% to 70% mean outer hair cell (OHC) loss in the basal turn of the cochlea, a reduction in ABR waveform and amplitude, and an increase in latencies of ABR waves I, II, and III. Combined CSP and kanamycin treatment produced 90% to 100% mean OHC loss in all rows of the basal turn of the cochlea, with no discernible ABR waveform corresponding to the region stimulated by a 4500 to 7000 Hz acoustic click. Combined treatment produced the most significant cortical medullary tubular necrosis and interstitial nephritis. Furthermore, this study reports for the first time localization of platinum in the inner ear.

Acute Kidney Injury↗

Orbital subperiosteal hematoma (epidural hematoma of the orbit).

Three cases are presented of subperiosteal hematomas, which can be thought of as epidural hematomas of the orbit. One occurred in a child associated with an episode of violent vomiting, the second in an adult with a history of remote head trauma who presented with a slowly progressive course suggestive of thyroid eye disease, and the third in a young patient after acute trauma probably associated with the injections of a local anesthetic agent or possibly the passage of a deep suture. Skull x-rays, computed tomography, and ultrasonographic examinations detected and localized the lesion in each case. Both patients who were operated on enjoyed prompt and total resolution of their symptoms after surgical extirpation of the lesion. In the third patient, the lesion regressed on its own.

Adult↗

Intravitreal autotransplantation of fibroblasts.

Tissue cultured skin fibroblasts autotransplanted into the vitreous cavity of rabbit eyes formed intravitreal strands that grew toward the medullary ray and optic nerve head and caused preretinal puckers and traction detachment. After four weeks, 32 of 51 eyes (63%) developed these changes. Light and electron microscopy revealed initial cell death. Remaining cells aligned themselves quickly into strands and began to multiply as shown by tritiated thymidine methyl incorporation. The appearance of cells that resemble myofibroblasts may explain the contractability of the strand. Because the effect of intraocular proliferation can be quantitated by the number of puckers and retinal detachments developing, this model may be useful for the study of therapeutic means to reduce intraocular proliferation.

Animals↗

Inhibition of intraocular proliferations with intravitreal corticosteroids.

Autotransplantation of one fourth million tissue cultured fibroblasts from rabbit rump skin into the vitreous cavity resulted in intravitreal strand formation and traction retinal detachment (27 of 47 eyes, 57%). A single intravitreal injection of 1 mg of dexamethasone alcohol inhibited fibroblast growth as judged by the significantly reduced number of retinal detachments (11 of 46 eyes, 24%). Retinal neovascularization that was observed when fibrous strands came into contact with vascularized retina (nine of 47 eyes, 19%) was also inhibited after corticosteroid application (two of 46 eyes, 4%).

Animals↗