[Stereoscopic visual evoked potential elicited by static random dot stereogram]

Using 16.56' visual disparity stimulation produced by television random dot stereogram (TVRDS), we recorded visual evoked potentials (VEPs) elicited from 35 normal subjects with and without breaking their stereopsis and 28 stereoblind subjects. The results showed that a constant negative-positive wave complex was observed in 33 of 35 normal subjects; this negative-positive wave-complex disappeared when the stereopsis was artificially inhibited by a prism and in the stereoblind group, and no VEP wave was elicited in all of the stereoblind patients except in one with paralytic strabismus. The results revealed that under this condition the VEPs elicited by TVRDS were specific VEPs related to visual disparity stimulation and were stereoscopic ones. The TVRDS is an effective electro-physiological means to examine the stereopsis objectively and a new way to approach the occurrence and development of stereopsis.

Molecular cloning and tissue distribution of PHAS-I, an intracellular target for insulin and growth factors

Although the actions of insulin and a number of growth factors that signal via protein-tyrosine kinase receptors are believed to involve increased phosphorylation of key intracellular proteins, relatively few of the downstream phosphoproteins have been identified. In this report we describe a cDNA encoding one of the most prominent insulin-stimulated phosphoproteins in rat adipocytes. The cDNA encodes a protein, designated PHAS-I, which has 117 amino acids and a M(r) of 12,400. When translated in vitro and subjected to SDS/PAGE, PHAS-I migrates anomalously, having an apparent M(r) of 21,000. The predicted amino acid composition is interesting in that approximately 45% of the PHAS-I protein is accounted for by only four amino acids--serine, threonine, proline, and glycine. The PHAS-I gene is expressed in a variety of tissues, although the highest levels of mRNA are present in fat and skeletal muscle, two of the most insulin-responsive tissues. The nucleotide and deduced amino acid sequences of PHAS-I differ from any that have been reported, and homology screening provided no clues concerning the function of the protein. However, in view of its tissue distribution and the fact that the protein is phosphorylated in response to insulin, we speculate that PHAS-I is important in insulin action.

The chromatographic behaviour of cephalosporins in gel filtration chromatography, a novel method to separate high molecular weight impurities

The interaction between cephalosporins and the dextran matrix of Sephadex gel in gel filtration chromatography has been thoroughly studied. Twelve cephalosporins with specific structures were examined under different chromatographic conditions, including 12 different mobile phases comprising inorganic or organic compounds of different charge or/and density of electrons on their negative ions, different types of Sephadex gel (Sephadex G-10 and Sephadex G-50) and different flow rates. It was found that the more negative the charge or/and density of electrons on the negative ions of buffer components, the more was the adsorption of cephalosporins on the solid phase; this indicated tht the mobile phase played an important rôle in gel filtration chromatography for cephalosporins. By choice of suitable chromatographic conditions, optimum separation of high molecular weight impurities from cephalosporins could be achieved. The novel method could be used as a routine method for the quality control of cephalosporin preparations.

Presence of hepatitis B surface antigen (HBsAg)-specific cytotoxic T cells in asymptomatic HBsAg carriers

To investigate whether there is any evidence of an immune stimulation against hepatitis B virus surface antigen (HBsAg) in asymptomatic HBsAg carriers, proliferative and cytotoxic responses to HBsAg were measured in their peripheral blood lymphocytes. Although the majority of asymptomatic carriers had no proliferative response to HBsAg, 3 (25%) of 12 carriers showed significant T cell proliferation against HBsAg. In addition, using HBsAg-expressing autologous lymphoblastoid cell line (LCL) as target cells, HBsAg-specific cytotoxic activity was found in 2 of 3 asymptomatic HBsAg carriers who had a proliferative response against HBsAg. Furthermore, 6 cytotoxic T lymphocyte (CTL) clones were isolated from 1 asymptomatic carrier. The epitope recognized by 2 CTL clones was mapped to the major HBsAg residues 158-172. These CTL clones were able to produce interferon-gamma, tumor necrosis factor-alpha, or granulocyte-macrophage colony-stimulating factor. These findings demonstrate the presence of HBsAg-specific, major histocompatibility complex class I-restricted CTL in asymptomatic HBsAg carriers.

[Establishment of a primary eye care network and creation of a cataract-free zone in Shunyi County of Beijing]

Based on the epidemiological survey of eye diseases in 1985, a primary eye care network was established in Shunyi County of Beijing in 1987. Cataract surgery was the primary measure for the prevention of blindness, with the aim of creating a cataract-free zone in the county. The activities included (1) establishment of a County Guiding Committee for the prevention of blindness; (2) establishment of a 3-levelled primary eye care network and a referral and monitor system; (3) training of 7 ophthalmologists, 449 eye care workers and 6 optometrists; (4) extensive publicity of knowledge for the prevention of blindness; (5) screening of low vision and blindness in which 815 cataract blind patients were identified; and (6) conducting benefit ophthalmic counselling services. Up to December, 1991, 667 cataract operations were performed, representing 81.84% of the total cataract blind, to meet the qualifications of a cataract-free zone. 90.64% of the blind were restored sight and 59.16% of the blind were able to resume work. Operative infection occurred in none and 97.42% of the operations had no complication.

An efficient control strategy for dosage regimens

In medical drug therapy, efficient dosage strategies are needed to maintain target drug concentrations. The relationship between the concentration of a drug and the dosages is often described by compartment models in which the parameters are unknown, although prior knowledge may be available and can be updated after blood samples are taken during the therapy. Currently MAP (maximum a posteriori) Bayesian is the most often used control strategy in this setting. We show by simulation in a one-compartment context that the performance of the MAP Bayesian strategy depends on the assumptions in prior distribution of the parameters as well as the cost function. We propose an alternative control strategy, VU, that outperforms and is more robust than the MAP Bayesian strategy in a variety of problem settings.

Cytomegalovirus DNA in arterial walls of patients with atherosclerosis

The biological properties of cytomegalovirus (CMV) are consistent with a potential role in the pathogenesis of atherosclerosis. The evidence of such a role has so far been circumstantial, but CMV nucleic acid is beginning to be reported with increasing frequency in the arterial wall. Arterial specimens from 135 patients who underwent vascular surgery for symptomatic atherosclerotic vessel disease were analyzed by PCR for the presence of CMV nucleic acid. Samples were studied from the atheromatous plaque area and from uninvolved aortic tissues of patients undergoing surgery for vascular disease. One primer pair (LA) was used for detection of a late gene, and two other primer pairs (E1 and E2) were used for the immediate early gene region. Serum antibody to CMV was measured by radioimmunoassay. With the late gene primer, CMV nucleic acid was found in 76% of the tissue specimens tested, whereas the E2 gene primer complementary to the transforming mtr2 region was reactive in 90% of the arterial samples. There was no significant difference in the prevalence of CMV DNA in atherosclerotic plaque tissue and in uninvolved aortic tissue from the patients. A second early gene primer was not reactive with the tissue specimens, although it gave positive results with the positive control of infectious virus. Serum antibody to CMV was detected in 86% of the patients in whose tissue CMV DNA was demonstrated. CMV DNA was detected in a high proportion of atherosclerotic plaque tissues as well as in uninvolved aortic tissue of surgical patients, suggesting that latent CMV infection of the arterial wall may be a common occurrence in patients with atherosclerosis.

What are the implications of cardiac infection with cytomegalovirus before heart transplantation?

To elucidate prognostic implications of recipient cytomegalovirus infection before heart transplantation, we prospectively followed the clinical outcome of 21 transplant recipients whose explanted hearts (myocardium and coronary arteries) were first examined for the presence of cytomegalovirus DNA with polymerase chain reaction. Subsequently, serial endomyocardial biopsy tissue samples obtained from the allograft during routine evaluation for rejection were analyzed by polymerase chain reaction for both an immediate early and late cytomegalovirus gene region of cytomegalovirus DNA. Humoral cytomegalovirus immunoglobulin G antibodies were also measured by radioimmunoassay. Both early and late antigens were present in 14 of 21 (67%) explants from patients with (12 of 15 explants) and without (2 of 6 explants) pretransplant cytomegalovirus antibodies. Although the presence of both early and late antigens was uncommon in allografts the first week after transplantation (5 of 20 allografts, 25%), their presence significantly increased at 1 month (14 of 21 allografts, 67%) and 2 to 3 months (13 of 17 allografts, 77%) regardless of pretransplantation cytomegalovirus antibody status. The presence of both early and late antigens in explant tissue strongly predicted allograft virus status during the follow-up periods. Of five patients in whom clinical cytomegalovirus disease subsequently developed, all had explants positive for both early and late antigens, and all allografts were positive for early and late antigens within 1 month after transplantation. These are the first prospective data to correlate pretransplantation serum antibodies and explant polymerase chain reaction status with the development of future allograft infections and overall clinical outcome.

Intravitreal pharmacokinetics of liposome-encapsulated amikacin in a rabbit model

BACKGROUND

Intravitreal injection of antibiotics has become a standard therapy for bacterial endophthalmitis. The duration of effective antimicrobial levels in the vitreous after single injection, however, may not be long enough to get optimal response. The authors prepared liposome-encapsulated amikacin for prolonging the duration of intravitreal therapeutic concentrations and investigated the intravitreal pharmacokinetics of the liposomes and amikacin in phosphate buffer solution (PBS) as control.

METHODS

The liposome-encapsulated amikacin was prepared by reverse-phase evaporation method. The intravitreal pharmacokinetics of the liposomes was compared with amikacin in PBS by fluorescence polarization immunoassay. Albino rabbits were randomly distributed into 12 groups. Rabbits in groups 1 to 6 and in groups I to VI (control groups) received an intravitreal injection of the liposome-encapsulated amikacin and amikacin in PBS, respectively.

RESULTS

The encapsulation rate of amikacin was 91%. The time of 50% spontaneous degradation (half-life) of the liposomes in PBS (38 degrees C, pH 7.4) was 47.6 days, and the time of 50% release (half-life) of the drug from the liposomes in PBS was 84.8 hours. The vitreous amikacin concentrations in groups 1 to 6 were significantly greater (P < 0.05) than those in control groups I to VI in every time interval, except in groups 1 to 3 at 1 hour after injection. The difference was particularly obvious in the endophthalmitis groups. The clearance of encapsulated amikacin in vitreous appeared to be related to the state of blood-ocular barrier and to the structural integrity of vitreous. The distribution, the absorption, and the elimination of encapsulated amikacin in vitreous showed the first-order kinetics.

CONCLUSION

The liposome-encapsulated amikacin prolonged half-life of the drug in vitreous. The results of the pharmacokinetic analysis suggested that in endophthalmitis, especially in severe cases, the liposomes may be preferable to conventional preparation.

A simple technique for blood collection in the pig

A simple technique for blood collection in pigs of body weight 15-40 kg is described. The subcutaneous abdominal vein was used for rapid collection of 5-20 ml of blood samples. The animals were premedicated with 10 mg/kg of ketamine and 600 micrograms of atropine given intramuscularly prior to blood collection.

An open reading frame in the Rhodospirillum rubrum plasmid, pKY1, similar to algA, encoding the bifunctional enzyme phosphomannose isomerase-guanosine diphospho-D-mannose pyrophosphorylase (PMI-GMP)

The nucleotide sequence of a BglII fragment (3188 bp) from the plasmid pKY1 of Rhodospirillum rubrum was determined. A significant similarity was found between the amino acid sequences deduced from the nucleotide sequence of BglII fragment with that of algA, encoding the bifunctional enzyme with both the activities of phosphomannose isomerase and guanosine diphospho-D-mannose pyrophosphorylase of Pseudomonas aeruginosa.

Gastrointestinal manifestations of neurofibromatosis in childhood

Von Recklinghausen's neurofibromatosis (VRN) is a familial disorder characterised by a generalized neuroectodermal dysplasia--symptomatic involvement of the gastrointestinal tract is rare. We report on our experience with two children who had proven gastrointestinal neurofibromas and highlight the need for careful assessment in children with VRN who develop abdominal pain.

[Radioimmunoassay of serum and CSF myelin basic protein and its application to patients with acute cerebrovascular accident]

Myelin basic protein (MBP) was measured in the serum and CSF of patients with acute cerebrovascular disease (CVD, 34 cases), demyelinating disorders (DMD, 30 cases) and other neurological diseases (OND, 26 cases) by using a double antibody radioimmunoassay (RIA). Patients with acute CVD had a mean serum MBP concentration and positivity rate much higher than those with DMD and OND. The differences were significant (P < 0.05). In CSF, MBP levels in patients with acute CVD and patients with DMD were significantly greater than those in OND patients (P < 0.05). The results also show that there was a linear relationship between the CSF MBP levels and the serum MBP levels in patients with acute CVD (r = 0.72, P < 0.01), but no such relationship in patients with DMD and OND. The amount of serum MBP was also significantly correlated to the severity of acute CVD, to the level of consciousness disorder and limb paralysis, and to the extent and site of the cerebral lesion at CT-scan (P < 0.05). This study shows that the measurement of brain specific MBP in serum as a marker of cerebral damage may have clinical value in the diagnosis and prognosis of patients with CVD.

A study of the detection of sperm antibody in cervical mucus with a modified immunobead method

OBJECTIVE

To develop a new immunobead binding test (IBT) procedure that will detect sperm antibody in cervical mucus (CM), especially in very small samples of mucus.

DESIGN

After the interaction of donor sperm with bromelin-dissolved CM, the motile sperm cells were separated from other cells and debris and then tested with a standard immunobead method.

SETTING

The CM and serum samples were obtained from a sequence of referred patients who were sent to this testing laboratory.

PATIENTS

There were 60 women who provided 64 samples of CM and 41 samples of blood serum. They were partners in infertile couples.

INTERVENTIONS

None.

MAIN OUTCOME MEASURE

A useful distinction was made between positive and negative results for the mucus samples by this CM-IBT procedure. The usable samples of mucus could be as little as 0.05 g (wet weight).

RESULTS

From the 60 women, seven mucus samples were positive; in the repeated testing, the same results were obtained with five of the six positive samples and seven of seven negative samples.

CONCLUSION

This method (CM-IBT) can be clinically useful for detecting sperm antibody in CM, especially because it is effective for tiny samples. In this method, the motile sperm cells are better separated from the debris after the incubation step. When the IBT was applied to the serum samples from the same women, there was no correlation between serum-IBT and CM-IBT, showing that both materials must be tested.

Immunopharmacological activity of cefodizime in young and elderly subjects: in vitro and ex vivo studies

The biological response modifying activities of cefodizime (CDZ), a new third-generation cephalosporin, were investigated in vitro and ex vivo. In vitro investigations using cells isolated from the blood of young healthy donors showed no stimulating activity of CDZ on peripheral blood lymphocytes, natural killer cell activity, IL-1 production by adherent mononuclear cells, PMN chemiluminescence or PMN chemotaxis. A slight but statistically insignificant increase in PMN phagocytosis and phagocytic index was observed in the same population. IL-1 production was increased in three subjects with low resting state values. In a controlled ex vivo study, 20 healthy elderly subjects selected on the basis of depressed phagocytic function were treated with CDZ 1 g i.m. b.i.d. or placebo for eight days. PMN function was determined at baseline and on the day after the last dose. In the CDZ group a significant increase in both phagocytosis and phagocytic index was found, while there were no changes in the placebo group. In conclusion, CDZ restored depressed PMN phagocytic function in a population of elderly subjects. Patients with impaired PMN function who require antibiotic treatment may benefit from this activity of CDZ.

Internalization of CD4 molecules in human T-cells demonstrated by immuno-electron microscopy

Internalization of CD4 molecules on human CD4-enriched T-cells was demonstrated by immunocytochemical electron microscopy. CD4+ T-cell subclones were obtained from normal human peripheral blood, followed by one-way MLC screening and co-culturing with IL-2. Fixed and non-fixed T-cell samples were indirectly immunolabeled with mouse anti-human CD4 monoclonal antibody and goat anti-mouse IgG conjugated with peroxidase. Unfixed T-cells were immunolabeled at 4 degrees C and then re-incubated for 5-45 min at 37 degrees C. The selected CD4+ T-cell subclones showed strong CD4 binding on the cell surface after IL-2 incubation. However, fresh T-cells, monocytes, bone marrow cells and CD8+ T-cells all stained negative for CD4. The distribution of CD4 molecules on the fixed cell surface showed a homogeneous pattern. Capping and internalization of CD4-antibody-peroxidase complexes from the cell surfaces were observed follow a pathway of receptor-mediated endocytosis in unfixed T cells. Endocytotic vesicles, vacuoles of diverse sizes and shapes near the cell membrane or deep in the cell center were found to contain CD4 molecules. Negatively stained Golgi saccules were observed up to 45 min after re-incubation. These results suggest that increased CD4 molecules can be induced on the surface of normal human T-cells in vitro. Internalization and accumulation of CD4 molecules occurred in CD4-enriched T-cells with IL-2 pretreatment.