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Biomedical subjects

M A Honig

Publications and source records attributed to M A Honig.

6 recordsLinked to original sources
PubMed1999

Corneal ulcers and the use of topical fluoroquinolones.

PURPOSE: To determine whether the widespread use of topical fluoroquinolones has changed the spectrum of ulcerative keratitis, and to determine how it has affected practice patterns in the treatment of corneal ulcers. METHODS: We retrospectively reviewed the charts of 48 consecutive patients with infectious corneal ulcers from 7/1/91 to 12/31/91 and 47 consecutive patients from 7/1/94 to 12/31/94. Patients were treated with intensive topical antibiotics (either standard fortified antibiotics or topical fluoroquinolones) at a frequency of at least every hour while awake. Some patients were admitted to the hospital, and some underwent scraping for smears and cultures. RESULTS: Ulcers which were seen in 1994 appear to have been more severe than those seen in 1991 as judged by the presence of more ulcers associated with hypopyons, (P< 0.05) but not with regard to the size of the infiltrate or epithelial defect. More ulcers in 1994 were treated on an outpatient basis (P< 0.02) and fewer ulcers were scraped and cultured than in 1991 (P< 0.001). Culture results from the 1991 and 1994 groups were similar. The most frequently isolated organisms were coagulase-negative Staphylococcus, Pseudomonas, Staphylococcus aureus, and Streptococcus spp. CONCLUSION: The spectrum of ulcerative keratitis at a tertiary referral center may be showing a trend towards more severe ulcers, but the causative agents responsible for the infection are unchanged.

Administration, Topical↗
PubMed1997

Clearance of postprandial and lipolytically modified human HDL in rabbits and rats.

Triglyceride (TG) enrichment of high density lipoproteins (HDL) in hypertriglyceridemic states renders the particles vulnerable to lipolysis, which reduces their size. In the present study we modified the size and composition of HDL in vivo in hypertriglyceridemic humans by administering a bolus of intravenous heparin, and tested the subsequent clearance of the isolated HDL particles in rabbits and rats. HDL was isolated by ultracentrifugation from 21 moderately hypertriglyceridemic humans, 5 h after ingestion of a high fat meal and then 15 min after an intravenous heparin bolus (60 U/kg). Postprandial large TG-rich preheparin HDL and small, TG-poor postheparin HDL were labeled with either 125I or 131I. The clearance of apoA-I associated with each HDL tracer was determined by injecting the tracers 1) simultaneously (n = 13) and 2) sequentially (n = 8) into male New Zealand White rabbits, an hepatic lipase-deficient animal, and 3) by injecting the tracers simultaneously into male Sprague-Dawley rats (n = 8), an animal that has hepatic lipase. Die-away curves of each radiolabeled tracer were analyzed using a two-pool model that assumes the existence of an intravascular pool in dynamic equilibrium with an extravascular pool. In the rabbit studies, the fractional catabolic rate (FCR) of small, postheparin TG-poor HDL was greater than the FCR of the larger TG-rich HDL (11% greater in the simultaneous study, P < 0.001, and 45% greater in the sequential study, P < 0.001). Opposite results were observed in rats as large TG-rich preheparin particles showed a greater FCR (1.8-fold) than smaller TG-poor postheparin HDL (P < 0.05). These data suggest that although size and composition of HDL can influence its catabolism, the effect is not always in the same direction and depends on other factors present in vivo.

Animals↗
PubMed1996

Forceps and vacuum injuries to the cornea: histopathologic features of twelve cases and review of the literature.

Histopathologic and ultrastructural features were examined from 11 cases of corneal injury from obstetrical forceps and one case from vacuum extraction. Four major types of histopathologic features were observed. Type I (n = 4) included large tears of Descemet's membrane with a fragment of Descemet's membrane extending into the anterior chamber at one end of the tear and scroll formation at the other end. Type II (n = 6) consisted of scrolls of Descemet's membrane at each margin of the original break. Type III (n = 2) included those with small breaks in Descemet's membrane and healing by fibrosis at and posterior to the original tear. Type IV (n = 1) contained a small break in Descemet's membrane with minimal fibrosis. Transmission electron microscopy revealed Descemet's scrolls and retrocorneal fibrous tissue. Scanning electron microscopy revealed folds in Descemet's membrane and attenuation or absence of endothelium. Spindle- and stellate-shaped cells and pigment granules were present in the area of the tear in most cases. A review of the literature is presented.

Adult↗
PubMed1989

Mood changes after right-hemisphere lesions.

Ninety-three patients with acute stroke lesions restricted to the right hemisphere were examined for the presence of mood changes. While 46 patients showed no mood changes, 19 were unduly cheerful, 17 had developed major depression, and 11 had developed minor depression. Although there were no significant between-groups differences in other demographic variables, neurological deficits, activities of daily living, cognitive impairment, or quality of social support, patients with major depression had a significantly higher frequency of familial history of psychiatric disorder and lesions of the parietal cortex than patients with either no mood change or major depression following left-hemisphere lesions. On the other hand, undue cheerfulness was significantly associated with lesions of the right frontal operculum. These findings suggest that major depression following right-hemisphere lesions may have a different aetiology and mechanism than major depression following left frontal or basal ganglia lesions.

Activities of Daily Living↗
PubMed1988

Neuronal and endothelial sites of acetylcholine synthesis and release associated with microvessels in rat cerebral cortex: ultrastructural and neurochemical studies.

We sought to establish what proportion of the cholinergic innervation of the cerebral cortex (CX) is associated with intraparenchymal blood vessels by using immunocytochemical and neurochemical techniques, and whether [3H]acetylcholine ([3H]ACh) is synthesized and released by elements associated with cortical microvessels (MV). MVs and, for comparison, tissue homogenates were prepared using sucrose gradient/differential ultracentrifugation methods. Efficacy of the separation technique was indicated by the activity of gamma-glutamyltranspeptidase (up to 29.2-fold enrichment), an endothelial cell marker enzyme, in the MV fraction and microscopy. The size of isolated microvessels ranged from 5 to 40 micron (o.d.) with 67.7% of the vessels less than 10 micron and 32.2% between 11 and 40 micron (690 vessels measured from 4 animals). By electron microscopy immunoreactive choline acetyltransferase (ChAT), the biosynthetic enzyme for ACh, was localized to: (a) axons and axon terminals opposed to the basal laminae of capillaries and small arterioles, and (b) capillary endothelial cells. ChAT-labeled elements associated with MVs were most prominent in layers I, III and V of the CX consistent with the local pattern of cholinergic innervation. The absolute amount of ACh synthesized (pmol Ach/100 mg wet wt.) by elements associated with cortical MVs was relatively small (2.3% total cortical homogenate activity). Inhibition of MV ChAT activity to 5% of control by the specific ChAT inhibitor, 4-naphthylvinylpyridine, and HPLC analysis of the product, indicated that authentic ACh was measured. Other tissues similarly synthesized small amounts of ACh relative to the CX, caudate nucleus (CN, 2.4%), cerebellum (CRB, 1.4%) and liver (LIV, 3.9%). Consistent with the known extent of the cholinergic innervation of the tissues examined, the rank order of ChAT associated for both MVs and homogenate were: CN greater than CX much greater than CRB greater than LIV. However, based on the specific activities of ChAT, cortical MVs have the remarkable capacity to synthesize ACh at rates 95% greater than cortical (S1 fraction) homogenate (59.0 +/- 3.5 nmol/mg protein/40 min; n = 7), which is enriched in nerve terminals. Except for LV (+11%), other tissues also had remarkably high ChAT activity in MV (% above corresponding homogenate; P less than 0.05, n = 5): CN (+269) and CRB (+313). Release of [3H]ACh from MVs and, for comparison, nerve terminals were graded to K+ depolarization stimulus (5-55 mM), maximal with 55 mM K+ and Ca2+ dependent.(ABSTRACT TRUNCATED AT 400 WORDS)

Acetylcholine↗