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Biomedical subjects

K H Spitzer

Publications and source records attributed to K H Spitzer.

6 recordsLinked to original sources
PubMed1994

Phacoemulsification--a senior surgeon's learning curve.

We sought to prospectively document and evaluate the learning curve of an experienced extracapsular surgeon making a supervised transition from extracapsular cataract extraction (ECCE) to phacoemulsification. Over a period of 2 weeks, 51 phacoemulsification procedures using an endocapsular nucleofractis technique were performed by a single senior surgeon at the Christian Medical College in Vellore, India under the supervision of a visiting US expert with more than 15 years' experience in the technique. Vitreous loss occurred in seven eyes (six prior to the stage of cortical aspiration); failure of capsulorhexis necessitated conversion to standard ECCE in four. Injury to the inferior iris during phacoemulsification was cosmetically significant in three eyes. Two eyes had mild persistent localized corneal edema, but there were no instances of permanent corneal damage. One eye had intraoperative displacement of the nucleus into the vitreous. In one eye with vitreous loss, the implanted intraocular lens dislocated into the vitreous cavity. Two patients had clinically detectable cystoid macular edema at 6 weeks. Eleven patients were lost to follow up after 3 weeks. Six weeks after surgery, 36 of the remaining 40 eyes (90%) had achieved a best-corrected visual acuity of 6/6. We conclude that phacoemulsification requires supervised learning, even for an experienced surgeon. Complications still occurred, but were restricted to the unfamiliar steps of the surgery. Factors identified in the first 2 days of surgery (10 cases) as critical in the smooth transition to phacoemulsification were careful selection of initial cases, a successful capsulorhexis, and hydrodissection with vigorous nucleus mobilization.(ABSTRACT TRUNCATED AT 250 WORDS)

Astigmatism↗
PubMed1985

Ca2+/calmodulin-dependent microtubule-associated protein 2 kinase: broad substrate specificity and multifunctional potential in diverse tissues.

In previous studies, we described a soluble Ca2+/calmodulin-dependent protein kinase which is the major Ca2+/calmodulin-dependent microtubule-associated protein 2 (MAP-2) kinase in rat brain [Schulman, H. (1984) J. Cell Biol. 99, 11-19; Kuret, J. A., & Schulman, H. (1984) Biochemistry 23, 5495-5504]. We now demonstrate that this protein kinase has broad substrate specificity. Consistent with a multifunctional role in cellular physiology, we show that in vitro the enzyme can phosphorylate numerous substrates of both neuronal and nonneuronal origin including vimentin, ribosomal protein S6, synapsin I, glycogen synthase, and myosin light chains. We have used MAP-2 to purify the enzyme from rat lung and show that the brain and lung kinases have nearly indistinguishable physical and biochemical properties. A Ca2+/calmodulin-dependent protein kinase was also detected in rat heart, rat spleen, and in the ring ganglia of the marine mollusk Aplysia californica. Partially purified MAP-2 kinase from each of these three sources displayed endogenous phosphorylation of a 54 000-dalton protein. Phosphopeptide analysis reveals a striking homology between this phosphoprotein and the 53 000-dalton autophosphorylated subunit of the major rat brain Ca2+/calmodulin-dependent protein kinase. The enzymes phosphorylated MAP-2, synapsin I, and vimentin at peptides that are identical with those phosphorylated by the rat brain kinase. This enzyme may be a multifunctional Ca2+/calmodulin-dependent protein kinase with a widespread distribution in nature which mediates some of the effects of Ca2+ on microtubules, intermediate filaments, and other cellular constituents in brain and other tissues.

Animals↗
PubMed1983

Posterior keratoconus associated with systemic abnormalities.

A 16-year-old girl with bilateral congenital posterior keratoconus of the localized type had corneal transplantation performed on one eye. Around the scarred central corneal cone there was a ring of Descemet's membrane with large knob-like excrescences. A small anterior subcapsular cataract was also present in this eye. The pattern of corneal scarring, as seen by electron microscopy, suggested an iridocorneal or iridocorneolenticular adhesion present at the 8- to 20-mm embryonic stage. Associated systemic defects, which could be dated to the same period, were median facial clefting and severe genitourinary abnormalities. Several external features, such as short stature, abnormal gait, broad nose, and upward displacement of the lateral canthi, were similar to those in the Haney-Falls syndrome of familial posterior keratoconus. No appreciable chromosomal abnormalities were found.

Abnormalities, Multiple↗
PubMed1979

Corneal transplantation in familial dysautonomia.

A 15-year-old girl with familial dysautonomia had acute corneal ulcerations while on a respiratory during a dysautonomic crisis. Within 18 days she developed irritating corneal ring calcifications. Subsequent corneal perforation in the left eye was treated successfully with a lamellar graft, followed later by a penetrating graft in the right eye under local anesthesia. Four days postoperatively, the patient died during a vomiting crisis. Neuropathologic studies showed marked cell reduction in the superior cervical and trigeminal ganglia, but slight in the ciliary. The foveas appeared immature and macular ganglion cells were mildly reduced. The corneal button and lamellar grafted cornea had severe thinning and superficial calcification. Keratoplasty in familial dysautonomia is considered hazardous because of the continual threat of vomiting crises, but with sufficient care may be worthwhile for corneal perforation or advanced corneal scarring.

Adolescent↗