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H Kaplan

Publications and source records attributed to H Kaplan.

At least 127 records · Page 7Linked to original sources
PubMed1988

Microcomputer analyses of clinical ERG, EOG, and other tests of retinal function.

The electroretinogram (ERG) and electro-oculogram (EOG) are two of the most frequently used visual electrodiagnostic tests of retinal function. The ERG and EOG are easily measured, but there are many engineering difficulties in processing their signal data because the response amplitudes are relatively small, and the relevant signals are buried in electromagnetic and biologic noise. These tests tend to be time consuming, so they lend themselves to automatic control. This article describes the engineering designs relative to a microprocessor-based electrophysiologic laboratory at Emory University Clinic to perform ERG, EOG, and other clinical tests of retinal function. A comparable system that offered both the ability to accept data from a variety of transducers and the flexibility to permit all of the planned testing protocols was not available from any commercial source.

Computers↗
PubMed1987

Phenytoin overdose.

Explore the source record for details and available documents.

Administration, Oral↗
PubMed1987

Competitive labeling as an approach to defining the binding surfaces of proteins: binding of monomeric insulin to lipid bilayers.

The free monomeric form of insulin is known to adsorb strongly to many different surfaces. A question of physiological relevance for which no previous studies have been reported is whether the monomeric form of insulin binds to lipid bilayers. In order to answer this question, it is necessary to carry out studies at the very dilute concentrations (less than 10(-6) M) necessary to obtain this species. We have approached this problem by applying the method of competitive labeling [Hefford, M.A., Evans, R.M., Oda, G., & Kaplan, H. (1985) Biochemistry 24, 867-874] to study insulin at concentrations as low as 3 X 10(-8) M, in the presence and absence of large unilamellar liposomes. With 1-fluoro-2,4-dinitrobenzene as the labeling reagent, the relative chemical reactivities of the functional groups of insulin were found to decrease markedly when insulin was incubated with liposomes consisting of egg lecithin and cholesterol (2:1 mol/mol) in 1.0 M KCl, pH 7.5 at 37 degrees C. The decrease for each functional group was found to directly correlate with its proximity to the dimer-forming surface of the monomer. It is concluded that insulin binds to lipid bilayers in a specific orientation, with the dimer-forming surface interacting with the bilayer. These results demonstrate the feasibility of applying competitive labeling to obtain structure-function relationships of membrane-interactive proteins in general and monomeric insulin in particular.

Adsorption↗
PubMed1987

[Jadassohn's sebaceous nevus and cutis verticis gyrata].

The presentation of this case has given rise to the following considerations: the possible association of liner nevus verrucosus with other cutaneous or extracutaneous malformations (skeletal, dental, ocular, neurologic, etc.) imposes the need to rule out such alterations with a view to their early correction or attenuation.

Abnormalities, Multiple↗
PubMed1987

[Axillary carcinoid papillomatosis in a linear verrucous nevus].

This report refers to the manifestation of an infrequent skin blastoma, with: Carcinoid papillomatosis developing on a zona-like verrucous nevus. An endeavor is made to determine the nosologic, etiologic, evolutionary and therapeutic aspects of both conditions.

Adolescent↗
PubMed1987

Optimal conditions for the induction of human mononuclear leukocytes by complexed polyinosinic-polycytidylic acid.

We have defined the optimal circumstances for the induction of human interferon alpha (Hu IFN alpha) in peripheral blood mononuclear cells (PBMC) using complexed polyinosinic-polycytidylic acids (poly rIrC). We have found that a poly rIrC concentration of only 0.1 microgram m/ml or 100 fold less than commonly used in fibroblasts produced maximal yields. Similarly, we have found that the optimal concentration of DEAE-D was 250 micrograms m/ml. Only a minimum exposure period of 30 minutes to the poly rIrC-DEAE-D mixture was found necessary, but the temperature of this incubation was not found to be a critical variant. Finally, we found that addition of exogenous calcium to the inducing solution failed to influence the ultimate titers of the IFN produced.

Calcium↗
PubMed1986

Structure-function relationships in the free insulin monomer.

The chemical properties of the functional groups of insulin were determined at a concentration (0.5 microM) where the predominant species of insulin is the free (unassociated) monomeric unit. The glycine N-terminus and the four tyrosine phenolic groups had the same properties as in the associated forms of insulin. On the other hand the lysine epsilon-amino group and the two histidine imidazole groups had substantially altered properties. Some alteration in the properties of the phenylalanine N-terminus was also observed. The reactivity-pH profile for the imidazole groups showed a second ionization with a pKa of 10.1 in addition to an ionization with a pKa of 6.8. On the basis of the X-ray-crystallographic structure of hexameric insulin the observed changes can be accounted for by disruption of monomer-monomer or dimer-dimer interactions in the associated states of insulin. It is concluded that the conformation of the monomeric unit of insulin is essentially the same in its free and associated states in solution.

Amino Acid Sequence↗
PubMed1986

Three-dimensional metabolic mapping of the freeze-trapped brain: effects of ischemia in the Mongolian gerbil.

The effects of unilateral carotid artery (left or right) occlusion on the three-dimensional metabolic mapping were studied in the Mongolian gerbil (Meriones unguiculatus). The brain was freeze-trapped by the liquid nitrogen funnel technique and was analyzed for the two-dimensional distribution of the reduced pyridine nucleotides and oxidized flavoprotein using a time-sharing micro-light guide surface fluorometer/reflectometer. The results could be summarized as follows. Bilateral carotid artery occlusion induced uniform effects in terms of redox state in the cerebral cortex and the olfactory bulbs. After unilateral carotid occlusion, the redox state of the ischemic ipsilateral hemisphere was higher and was not affected by blood volume changes as evaluated from the reflectance signal scanned in several brains. The narrow band of tissue near the midline of the ischemic hemisphere connected to the contralateral hemisphere blood supply appeared in a large number of gerbils. The anomaly in the redox state of the intracellular space also appeared in subcortical structures, as seen in all the two-dimensional mappings measured. It seems that blood circulation to the two olfactory bulbs is connected to the same blood vessel. It is suggested that unilateral carotid artery-occluded gerbils may show large variability inside the same hemisphere and therefore results must be evaluated very carefully.

Animals↗
PubMed1986

Hormonal therapy of cryptorchidism. A randomized, double-blind study comparing human chorionic gonadotropin and gonadotropin-releasing hormone.

We conducted a randomized, double-blind study comparing intranasal gonadotropin-releasing hormone (1.2 mg per day for 28 days) with parenteral human chorionic gonadotropin (3300 IU per week for four weeks) in the treatment of cryptorchidism in 33 boys one to five years old (29 with unilateral and 4 with bilateral cryptorchidism). Testicular descent into the scrotum occurred in 3 of the 16 patients (19 percent) treated with gonadotropin-releasing hormone and in 1 of the 17 (6 percent) treated with human chorionic gonadotropin (P = 0.23). The mean luteinizing hormone and testosterone levels were similar in both groups before treatment. During treatment, the testosterone levels were significantly increased in both groups, but higher levels occurred in the group treated with human chorionic gonadotropin (P less than 0.05). In a parallel (but uncontrolled) study of five boys with retractile testes (defined as a nonscrotal testis that could be manipulated into the bottom of the scrotum) who were originally excluded from the main protocol but were treated with the same regimen of human chorionic gonadotropin, descent into the scrotum occurred in all patients. We conclude that hormonal therapy with either gonadotropin-releasing hormone or human chorionic gonadotropin is, in most cases, ineffective in promoting testicular descent of true cryptorchid testes. However, short-term treatment with human chorionic gonadotropin is very effective in producing descent of retractile testes. These results suggest that the wide discrepancies in apparent efficacy in previous trials of hormonal therapy of cryptorchidism may have been due to inclusion in those studies of various proportions of patients with retractile testes.

Administration, Intranasal↗
PubMed1986

Invasive mucormycosis in a non-immunocompromised patient.

Primary invasive cutaneous mucormycosis in a non-immunocompromised patient is described. Cultures from the infected tissues yielded a zygomycete which was identified as Saksenaea vasiformis. The patient was successfully treated with debridement of the lesion and amphotericin B.

Aged↗
PubMed1986

[Giant hamartomatous nevus of undescribed complexity (development of an infiltrating malignant melanoma)].

A case is reported of complex hamartoma with the aspect of a giant pigmented nevus, localized in one of the lower extremities. Histological examination revealed the involvement of different embryonal layers in order to give rise to dissimilar types of nevi: flat pigmented nevus, intradermal cellular nevus, epidermal verrucous nevus, Jadassohn's sebaceous nevus; Hoffman-Zurhelle's superficial lipomatous nevus, and fibrous hamartoma of the manifested at infancy. This malformation and more specifically the nevus cells constitute the subsequent transformation into an infiltrating malignant blastoma (malignant melanoma).

Aged↗
PubMed1985

Unusual chemical properties of N-terminal histidine residues of glucagon and vasoactive intestinal peptide.

An N-terminal histidine residue of a protein or peptide has two functional groups, viz., an alpha-amino group and an imidazole group. A new procedure, based on the competitive labeling approach described by Duggleby and Kaplan [Duggleby, R. G., & Kaplan, H. (1975) Biochemistry 14, 5168-5175], has been developed by which the chemical reactivity of each functional group in such a residue can be determined as a function of pH. Only very small amounts of material are required, which makes it possible to determine the chemical properties in dilute solution or in proteins and polypeptides that can be obtained in only minute quantities. With this approach, the reactivity of the alpha-amino group of histidylglycine toward 1-fluoro-2,4-dinitrobenzene gave an apparent pKa value of 7.64 +/- 0.07 at 37 degrees C, in good agreement with a value of 7.69 +/- 0.02 obtained by acid-base titration. However, the reactivity of the imidazole function gave an apparent pKa value of 7.16 +/- 0.07 as compared to the pKa value of 5.85 +/- 0.01 obtained by acid-base titration. Similarly, in glucagon and vasoactive intestinal peptide (VIP), apparent pKa values of 7.60 +/- 0.04 and 7.88 +/- 0.18, respectively, were obtained for the alpha-amino of their N-terminal histidine, and pKa values of 7.43 +/- 0.09 and 7.59 +/- 0.18 were obtained for the imidazole function.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Psychometric profiles and facial pain.

The myofacial pain-dysfunction syndrome and atypical facial pain are the most prevalent chronic pain disorders of the facial region. Previously, the myofacial pain-dysfunction syndrome included all TMJ/masticatory muscle pain, jaw dysfunction, and joint clicking. We have segregated two major subgroups subsumed within this diagnostic classification and have assigned them to a myogenic facial pain (MFP) group and a TMJ internal derangement (TMJID) group. Significant age and personality differences were uncovered when these subpopulations were compared to subjects with atypical facial pain (AFP). Both MFP and TMJID groups are relatively homologous, involving younger persons than AFP subjects. Alternatively, when MFP, TMJID, and AFP subjects were compared for differences in MMPI psychometric scales, MFP and AFP subjects exhibited significantly higher scores, particularly for hypochondriasis, depression, and hysteria, than did TMJID subjects. It is concluded that subcategorization of myofascial pain-dysfunction patients into a myogenic pain group and a TMJ internal derangement group is justified on the basis of psychometric differences. Furthermore, psychopathologic factors are more significant among MFP and AFP subjects than among TMJID patients.

Adult↗
PubMed1985

Meningeal carcinomatosis due to basal cell carcinoma.

A case of meningeal carcinomatosis due to metastasizing basal cell carcinoma is reported. The patient was a 34-year-old woman who had a recurrent basal cell carcinoma of the upper eyelid with deep invasion. In spite of extensive surgery and radiotherapy, multiple bone metastases developed, and the patient eventually died of meningeal carcinomatosis. The possible pathogenic mechanisms of meningeal the present case, cancer cells reached the leptomeninges from adjacent vertebral metastases. It is suggested that the possibility of meningeal carcinomatosis should be considered in every patient with cancer and multiple vertebral metastases, particularly when neurologic signs involving the brain, cranial nerves, or spinal nerves are present.

Adult↗
PubMed1985

Giant cell tumor of the proximal radius.

Giant cell tumor of bones are usually located in the long tubular bones and rarely located in the proximal end of the radius. This is a case report of a giant cell tumor in the proximal radius in a 35-year-old woman treated successfully with curettage and bank bone graft.

Adult↗