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Biomedical subjects

J S Mindel

Publications and source records attributed to J S Mindel.

At least 37 records · Page 2Linked to original sources
PubMed1983

Bilateral intracavernous carotid aneurysms mimicking a prolactin-secreting pituitary tumor.

The triad of hyperprolactinemia, ophthalmoplegia, and radiologic abnormalities of the sell turcica suggest a tumor in the area of the pituitary gland. A new association--bilateral intracavernous carotid aneurysms--is presented. Two elderly women had extraocular muscle palsies and elevated serum prolactin levels of 71 and 32 ng/ml (normal: less than 20 ng/ml). In the former, a high-resolution computed tomography scan made after contrast medium injection was incorrectly interpreted as demonstrating a pituitary tumor; cerebral arteriography revealed bilateral aneurysms. In the other patient, a computed tomography scan after contrast medium injection demonstrated the bilateral aneurysms, and these were confirmed by radionuclide angiography.

Aged↗
PubMed1983

Succinyldicholine and the basic ocular deviation.

We measured the ocular positions of conscious and anesthetized subjects from photographs. We obtained the conscious basic horizontal deviation by using the cover-uncover test. Intravenously administered succinyldicholine chloride, 2 mg/kg of body weight, returned the eyes of 15 anesthetized volunteers to positions that agreed well with those of their conscious horizontal basic deviations in the primary position. The mean ratio (+/- S.E.) calculated by dividing the horizontal interlimbal distance 90 seconds after drug injection by that of the same subject's horizontal interlimbal conscious basic deviation was 0.99 +/- 0.01. This result supported the theory that the multiply innervated (en grappe) extraocular muscle fibers were responsible for the basic deviation. Macaca nemestrina monkeys and baboons proved to be unsuitable primate models for the human succinyldicholine response. In humans, the drug-induced ocular position was often vertically above or below the primary position. The associated horizontal deviation appeared to follow the physiologic V pattern, being more divergent if the eyes were rotated up and more convergent if the eyes were rotated down. In one third of the subjects this vertical deviation resulted in drug-induced horizontal interlimbal distances that disagreed by more than 5% with those of the conscious basic deviation in the primary position. This effect makes succinyldicholine of little value for making quantitative estimates of the amount of ocular muscle surgery to be performed during strabismus correction procedures. We injected succinyldicholine at the conclusion of strabismus surgery in eight subjects to determine if the drug-induced ocular positions would predict the postoperative results. The muscles operated on responded as though temporarily paretic. The drug-induced ocular positions bore no resemblance to the postoperative results.

Adult↗
PubMed1983

Diffuse choroidal atrophy and Klinefelter syndrome.

We report the first case of diffuse choroidal atrophy associated with Klinefelter syndrome. Retinal findings included midperipheral bone corpuscular pigmentation, large areas suggestive of choroidal atrophy, and unusual golden crystalline structures that apparently were mainly in the neurosensory retina. A sensorineural hearing deficit was also noted. Biochemical studies, including amino acid blood levels, were within normal limits. This case is of interest because of the rarity of association between Klinefelter syndrome and retinal or, in fact, any ocular abnormalities.

Atrophy↗
PubMed1983

An unusual presentation of isolated optic nerve sarcoidosis.

A 32-year old diabetic female had unilateral reduced vision (20/30) in an eye having the ophthalmoscopic appearance of papillophlebitis of the optic nerve head. After an apparently benign course, with recovery, the optic disc became edematous again and a central retinal vein occlusion blinded the eye. Thereafter, an avascular bilobed mass progressively protruded from the optic nerve head. Computerized tomography demonstrated uniform thickening of the optic nerve from the globe through the optic canal. The radiographic appearance was consistent with an optic nerve glioma or meningioma. Spinal fluid, chest x-ray, and serum angiotensin converting enzyme activity were normal. Tuberculin skin test was positive. Optic nerve biopsy demonstrated a noncaseating granuloma and a subsequent Kveim test was positive. Isolated optic nerve sarcoidosis may exist without other systemic manifestations. The appearance on computerized tomography may be similar to that of an optic nerve glioma or meningioma.

Adult↗
PubMed1982

The effect of echothiophate on the biphasic response of rabbit ocular pressure to dipivefrin.

A time-course study was performed on the intraocular pressure response of pigmented rabbit eyes. Dipivefrin administration produced in initial hypertensive phase lasting less than two hours followed by a prolonged hypotensive phase. Echothiophate iodide therapy produced a more pronounced and prolonged hypertensive response; there was no hypotensive phase. Administration of echothiophate plus dipivefrin resulted in a hypertensive phase similar to that from echothiophate alone; as previously reported, this combination was not followed by a hypotensive phase. The alpha-blocker phentolamine mesylate prevented the echothiophate-induced hypertension. When dipivefrin was administered with echothiophate plus phentolamine, there was an immediate hypotensive effect. It was concluded that the hypertensive effect of echothiophate in pigmented rabbit eyes may mask the hypotensive action of dipivefrin. This, rather than an echothiophate-induced inhibition of esterases, may explain why combination therapy with these drugs seemed ineffective.

Animals↗
PubMed1981

Dipivefrin and echothiophate. Efficacy of combined use in human beings.

In a previous study, pretreatment of rabbit eyes with echothiophate iodide prevented the ocular hypotensive effect of dipivefrin. The present masked study, using inpatient volunteers and nurse-administered drops, investigated whether a similar antagonism of action occurred in human beings. Eight volunteers received 0.25% echothiophate iodide twice a day in both eyes for three weeks. During the second week of therapy, one eye also received 0.25% dipivefrin twice a day and the contralateral eye received 2% epinephrine hydrochloride twice a day. During the third week of therapy, the eyes receiving dipivefrin and epinephrine were reversed. In four volunteers, dipivefrin plus echothiophate produced a significantly greater reduction in intraocular pressure than epinephrine plus echothiophate. As a group the eight eyes treated with dipivefrin plus echothiophate had significantly lower IOPs than the eyes treated with epinephrine plus echothiophate during the second week of therapy. Epinephrine plus echothiophate was never superior to dipivefrin plus echothiophate. Dipivefrin seemed to be effective during combination therapy with echothiophate.

Drug Therapy, Combination↗
PubMed1981

Miosis from echothiophate in patients with total oculomotor nerve paralysis from intracranial abnormalities.

Seven subjects with intracranial pathologic abnormalities received bilateral instillations of echothiophate. Six had unilateral third (oculomotor) nerve paralysis; one had unilateral third nerve paresis. All 14 eyes became miotic. Miosis was greater in the defective eye in three subjects, greater in the normal eye in two subjects, and equal in two subjects. The neurons originating in the ciliary ganglion and terminating on the sphincter pupillae muscle may exhibit spontaneous activity. Echothiophate, by preventing acetylcholine hydrolysis, may have allowed this transmitter to accumulate and to produce miosis. The amount of maximal miosis in the abnormal eye after bilateral instillation of echothiophate drops may vary from that in the normal eye. The causes of this variation include denervation supersensitivity of the sphincter pupillae muscle, partial paresis of the dilator pupillae muscle, and increased drug penetration in the abnormal eye.

Adult↗
PubMed1981

Ocular ergotamine tartrate toxicity during treatment of Vacor-induced orthostatic hypotension.

A 20-year-old woman developed severe orthostatic hypotension after attempting suicide by ingesting the rodenticide, Vacor. Oral ergotamine tartrate, 6 mg a day, was useful in treating the orthostatic hypotension. However, a bilateral toxic retinal vasculopathy, consisting of a severe generalized vasoconstriction and mild macular edema, occurred within three weeks. Additional findings were an extinguished electroretinogram and a reduced dark-adaptation retinal sensitivity; because we performed these two tests after instituting ergotamine therapy we do not know whether to attribute their abnormal results to Vacor toxicity, ergotamine toxicity, or a combination of the two.

Adult↗
PubMed1980

Comparative ocular pressure elevation by medrysone, fluorometholone, and dexamethasone phosphate.

In age-, race-, and sex-matched groups, the relative abilities of medrysone, fluorometholone, and dexamethasone phosphate to elevate intraocular pressure were compared in a masked manner. Compliance was controlled by drops being given by nursing personnel. The 18 male hospitalized volunteers received commercial preparations of one of the corticosteroids to each eye four times a day for six weeks. The relative ability of medrysone, fluorometholone, and dexamethasone phosphate to raise IOP was 1, 4, and 7.6, respectively.

Administration, Topical↗
PubMed1980

Is phenylephrine pivalate a prodrug?

Phenylephrine pivalate has been assumed to be a prodrug devoid of important intrinsic activity because of its structural similarity to dipivefrin (dipivaly epinephrine). However, unlike dipivefrin, the pharmacologic activity of phenylephrine pivalate was not prevented by prior administration of echothiophate iodide. Rabbits pretreated bilaterally with 0.25% echothiophate for two and seven days had similar mydriasis, both in quantity and duration, after receiving 10% phenylephrine hydrochloride to one eye and 1% phenylephrine pivalate to the other eye. This as consistent with the hypothesis that the phenylephrine pivalate molecule has important alpha-adrenergic activity regardless of whether it is converted to phenylephrine.

Animals↗
PubMed1980

Succinyldicholine-induced return of the eyes to the basic deviation: a motion picture study.

Succinyldicholine 2 mg/kg body weight returned the eyes of 20 anesthetized subjects to the same basic horizontal position as when conscious. The distance between the two eyes, as measured from motion pictures, agreed when the patient was in the conscious state and succinyldicholine-stimulated unconscious state by 99 +/- 10%. Since succinyldicholine has been shown by others to selectively produce a sustained contraction of en grappe muscle fibers, these muscle fibers are implicated as determinants of the basic ocular position and a cause of strabismus.

Adolescent↗
PubMed1979

Dipivefrin and echothiophate: contraindications to combined use.

A study was undertaken to determine whether the antiesterase activity of echothiophate iodide would prevent the conversion of dipivefrin to epinephrine. Dipivefrin was administered singly and in combination with echothiophate to 24 adult rabbits. Administration of dipivefrin lowered the intraocular pressure (IOP) 8 +/- 1 mm Hg (P less than .001). When echothiophate was given before and concomitant with dipivefrin, there was no further decrease in IOP compared with that produced by echothiophate alone (5 +/- 1 mm Hg). Addition of epinephrine to eyes receiving dipivefrin plus echothiophate resulted in a significant additional decrease in IOP of 4 +/- 1 mm Hg (P less than .001). When echothiophate was given after dipivefrin had lowered the IOP and both drugs were continued, the IOP rose to baseline levels. These results fit the theory that the esterase converting dipivefrin to epinephrine is inactivated by cholinesterase inhibitors. The clinical use of cholinesterase inhibitors and dipivefrin may be contraindicated.

Administration, Topical↗
PubMed1979

Similarity of the intraocular pressure response to different corticosteroid esters when compliance is controlled.

Fifty-four subjects with initial intraocular pressures under 20 mm Hg received a different commercial corticosteroid ester of prednisolone or dexamethasone in each eye for three to six weeks. Compliance was controlled. The intraocular pressure responses of the two eyes of a subject were similar. It was concluded that the absorptions of all four corticosteroids were in excess of the minimum amounts needed to maximally elevate pressure. Subjects complained that prednisolone acetate was irritating. Corticosteroid-induced uveitis developed in 3% (3) of the eyes.

Acetates↗
PubMed1978

Value of hyaluronidase in ocular surgical akinesia.

In a study of 27 cases of surgery for cataract extraction, mepivacaine 2% with hyaluronidase was found to shorten the induction times of facial nerve and retrobulbar blocks when compared to injections of mepivacaine 2% alone. The mean induction time of facial nerve blocks with hyaluronidase was 1.3 +/- 0.4 minutes. This was significantly (P less than .01) shorter than the mean induction time without hyaluronidase, 2.9 +/- 1.8 minutes. The use of hyaluronidase significantly (P less than .02) shortened the induction time of retrobulbar blocks. The median induction time with hyaluronidase was three minutes, whereas that without hyaluronidase was ten minutes. However, the use of hyaluronidase did not significantly (.25 less than P less than .50) alter the success rate of retrobulbar blocks.

Adjuvants, Anesthesia↗