Intracellular recordings from a biplexiform ganglion cell in macaque retina, stained with horseradish peroxidase

A biplexiform ganglion cell, which is characterized by dendritic contacts with rods, has been penetrated with an HRP-filled microelectrode in the retina of Macaca fascicularis. Its fine curvy axon could be traced to the optic disc. One of several dendritic processes ascended through all retinal layers and ended in the layer of rod spherules. Under all conditions of chromatic adaption, the cell produced depolarizing responses with a rapid onset and a slow decay. Besides a strong rod input the recordings indicate signals from at least two spectrally different cone mechanisms.

Rhytidectomy in male patients

We have reviewed the face lifting procedures performed in twenty-seven of our male patients performed during the years, 1979-1980. Their pre-operative and post-operative appearances have been carefully analyzed as to the best method of treatment as well as the risks and complications of these operations. This discussion includes an explanation of our current operative techniques for male face lifting.

Effect of healing on small internal diameter arterial graft compliance

Porosity is an essential component for long term function of small internal diameter synthetic vascular prostheses. Theoretically, porosity is required for healing by providing a scaffold for ingrowth of periprosthetic tissues. Porosity may be required for transfer of fluids and ions in prostheses even if tissue ingrowth does not occur. Increased permeability of vascular grafts has been shown to enhance tissue incorporation. Implants with pore sizes greater than 10 microns but less than 45 microns become ingrown with fibrohistiocytic tissue and capillaries. Implants with pore sizes greater than 45 microns are ingrown with organized fibrous tissue and minimal histiocytic response. The phenomenon of differential ingrowth may have important functional significance. Prostheses which heal with organized fibrous tissue have the potential for long term contracture, strangulation of vascularity and calcification. Fibrohistiocytic tissue has low mechanical strength and does not appear to contract or calcify. Elastomeric microporous vascular prostheses which are minimally ingrown or ingrown with fibrohistiocytic tissue maintain compliance after months of implantation. This study was designated to determine the effects of healing on the compliance of small internal diameter vascular replacements and to correlate the compliance to patency rates.

Synaptic patterns and response properties of bipolar and ganglion cells in the cat retina

After intracellular recording, bipolar cells of the cat retina have been stained with HRP and their contacts in the outer and inner plexiform layers examined by electron microscopy. Rod bipolars and cone bipolar cb6 make invaginating, ribbon related contacts with photoreceptors, hyperpolarize in response to light, and have axons terminating in layer b of the IPL. The axon terminal of cb2 ends in layer a of the IPL and its basal contacts with cones mediate hyperpolarizing light-responses. Cone bipolar cb5 is a center-depolarizing type with an axon ending in layer b but its cone contacts are at semi-invaginating basal junctions. Except for the amacrine-contacting rod bipolar cell, all cone bipolar types synapse with both amacrine and ganglion cells in the inner plexiform layer. In addition cb5 contacts AII amacrine cells with large gap junctions, and is physiologically rod dominated.

Rod pathways in the retina of the cat

Neurons involved in the transfer of rod signals to the ganglion cells in the retina of the cat have been recorded from and stained with horseradish peroxidase (HRP) and their synaptic connections determined by electron microscopy. The single morphological type of rod bipolar cell responds with a sustained hyperpolarization to light and in turn drives at least five morphologically different types of amacrine cells, each of which has a unique response pattern. Two amacrines respond with either a transient (AII) or a sustained (A17) depolarization to light, while three amacrines give transient (A8) or sustained (A6, A13) hyperpolarizations. Circuitry whereby rod signals reach both on-centre and off-centre ganglion cells is discussed.

The effects of plasma and salivary constituents on dentin permeability

The experiments described in this report were designed to determine the possible influence of plasma and salivary constituents on dentin permeability, in vitro. The results indicate that plasma, serum, and whole (mixed) saliva are all capable of causing immediate reductions in dentin permeability. Individual plasma protein fractions and several different types of bacteria were also effective in reducing the ease with which fluid can move across dentin. These observations may provide a mechanism for the "spontaneous" reductions in dentin sensitivity seen by clinicians following periodontal therapy.

Intestinal permeability in children with Crohn's disease and coeliac disease

Mannitol and lactulose were used as probe molecules to measure intestinal permeability in children with active small-bowel Crohn's disease and with untreated coeliac disease. Mannitol and lactulose were administered by mouth in a moderately hypertonic solution (580 mmol (mosmol)/l), and results were expressed as the ratio of the molecules excreted in urine over five hours. Patients with Crohn's disease had a sixfold increase in permeability (due to increased lactulose permeability) and those with coeliac disease a fivefold increase (due to decreased mannitol permeability). From these results the test offers potential as a noninvasive investigation in children with small-bowel disease.

Noninvasive evaluation of peripheral vascular disease using transcutaneous oxygen tension

Transcutaneous oxygen tension (PtcO2) was used for noninvasive determination of blood supply in 25 patients evaluated for peripheral arterial disease. PtcO2 values were compared with segmental Doppler pressure, pulse volume recording, pulse reappearance time, and angiography in patients being evaluated for wound healing problems, amputations, and peripheral bypass procedures. PtcO2 was measured using a heated (45 degrees C) Clark polarographic electrode to quantitate the oxygen which diffuses from the dermal capillaries to the skin surface. Control PtcO2 values recorded over the chest or shoulder taken while patients were breathing room air were 78 +/- 8 mm Hg. PtcO2 values greater than 50 mm Hg predicted success for levels of amputation and for wound healing without reconstructive procedures; values of 40 mm Hg or less were associated with continued wound problems and complication after amputation. Increased PtcO2 values after vascular reconstruction of the legs predicted improved clinical status on follow-up examinations up to 6 months. PtcO2 predicted the extent of vascular disease as well as the other noninvasive tests and angiography. We conclude that (1) PtcO2 tension is a simple, accurate, noninvasive method to determine the appropriate level of amputation, wound healing potential, and effectiveness of bypass procedures, and (2) PtcO2 values correlate well with angiography and noninvasive evaluations.

Failure of Padac test strips to detect staphylococcal beta-lactamase

Padac test strips failed to detect the production of beta-lactamase by 10 strains of penicillin-resistant staphylococci.

AII amacrine cells quicken time course of rod signals in the cat retina

1. In a perfused eyecup preparation, AII amacrine cells of the cat retina were penetrated with glass microelectrodes and their electrical responses to photic stimuli recorded. 2. Intracellular injections of the stains Procion, lucifer, or horseradish peroxidase revealed dendritic tree diameters of 30-80 micrometers (48 +/- 16 micrometers, mean +/0 SD) and cell body diameters from 7 to 12 micrometers (9 +/- 3 micrometers) for these cells. The dendrites were broadly stratified throughout the inner plexiform layer (IPL) but possessed large, terminal varicosities in the IPL and inner nuclear lyer (INL) proximal to the cell body. 3. The waveform of these cells in response to photic stimulation suggested division into four components: a) an initial rapid depolarization of the cell membrane followed by a slower decay toward the dark level; b) suppression of the dark noise of the cell; c) with dim or moderately intense stimuli, an off-hyperpolarization; d) in some cases a hyperpolarizing surround response. 4. The receptive fields of AII cells have been characterized using spatial stimuli consisting of long narrow slits. Curves have been fitted to spatial data using two space constants, one for the center mechanism and an opposing one for the surround. For the central mechanism, space constants ranged from 20 to 80 micrometers (46 +/- 22 micrometers), while for the surround they ranged from 60 to 130 micrometers (85 +/- 28 micrometers). The mean half-width of the center mechanism, calculated from the mean space constant, was about 0.25 degrees of visual angle (64 micrometers). The receptive-field properties of AII amacrine cells resemble those of center-depolarizing bipolar cells of other species. 5. Spectral studies of AII amacrine cells reveal that they are rod driven at all criterion voltage levels. Furthermore, adaptation of the rods by rod-saturating backgrounds eliminates 95% of the response amplitude of the AII amacrine cells. Under these conditions the tiny response component remaining is driven by the cat's long wavelength (556-nm peak) cones. 6. AII amacrine cells depolarize to rod stimulation more rapidly than other rod-dominated cells, such as rod bipolar cells, which hyperpolarize. For stimuli corresponding to about 10% of rod saturation, the latency to half-maximum amplitude is about 65 ms for AII cells, 40 ms faster than rod-dominated hyperpolarizing units. The leading edge of the response waveform for AII cells is also much more restricted in time. With the above stimulus it requires about 20 ms to increase from 25 to 75% of its peak, a period almost 4 times shorter than required by rod-dominated S-potential responses. With saturating stimuli the AII response requires only 5 ms to increase from 25 ot 75% of its peak. 7. Although prominent in the rod system, AII amacrine cells do not appear to be able to detect single quantum events. Threshold signals require the bleaching of about 200 rhodopsin molecules within a receptive field containing some 1,300 rods...

Virus-specific IgG and IgM antibodies in normal and immunocompromised subjects infected with cytomegalovirus

Levels of IgG and IgM antibodies t human cytomegalovirus (CMV) were measured using a solid-phase radioimmunoassay. Individuals positive by complement-fixation test consistently had detectable IgG titers by radioimmunoassay, but no quantitative relationship was apparent. An elevated IgM titer was considered specific for CMV infection because sera from individuals with other herpesvirus infections did not cross-react. In patients with mononucleosis, elevated titers of IgM antibody to CMV correlated (P less than 0.001) with active infection and were highest during viremia. Titers of IgG antibody to CMV during and after symptomatic infection were similar to those of asymptomatic positive individuals. Increases in CMV-specific IGM were observed in both primary and reactivated infections in cardiac transplant recipients. In a small group of cardiac transplant recipients with recurrent symptomatic disease, IgM titers were low at the time of viruria and did not increase with CMV tissue involvement, a result which suggests that quantitative deficiencies in IgM may be related to the severity of CMV infections.

Spontaneous Dissecting Aneurysm of the Extracranial Vertebral Artery

Spontaneous dissection of a cervical vertebral artery secondary to fibromuscular hyperplasia is uncommon, is often painful, and may be followed after a latent interval by further symptoms of embolism, occlusion, or hemorrhage. Accordingly, the lesion is potentially hazardous and warrants treatment when recognized.

Spontaneous dissecting aneurysm of the extracranial vertebral artery

Spontaneous dissection of a cervical vertebral artery secondary to fibromuscular hyperplasia is uncommon, is often painful, and may be followed after a latent interval by further symptoms of embolism, occlusion, or hemorrhage. Accordingly, the lesion is potentially hazardous and warrants treatment when recognized.

Dentin hydraulic conductance: changes produced by red blood cells

Red blood cells were forced into dentinal tubules in vitro under known hydrostatic pressures. This resulted in a 1 7-fold fall in the hydraulic conductance of dentin. The histologic appearance of red blood cells forced into dentin in vitro was very similar to that found in dog pulps following full crown preparations without adequate cooling in vivo.

Pressures created by dental injections

In routine dental practice, anesthetic solutions are injected into tissue sites of widely different distensibilities, under a variety of pressures. The purpose of the present study, during simulated dental practice, was to determine the maximum injection pressures obtained by clinicians during injections in dogs. Regular aspirating dental syringes were used together with dental anesthetic cartridges filled with isotonic saline. Maximum operator injection pressures ranged from 330 to 660 psi (17,061-34,122 mmHg). Those injection sites that were least distensible gave the highest maximum injection pressures: interosseous (21,559 mmHg); incisive papilla (18,224 mmHg); periodontal (17,630 mmHg); hard palate (11,322 mmHg); and intrapulpal (8918 mmHg). More distensible tissue sites gave much lower pressures. The data indicate that dental injection pressures vary widely from several hundred mmHg to several hundred psi, depending on the clinician's physical effort and the distensibility of the tissue.

Parental assessment of temperament in handicapped children

The New York Longitudinal Study (NYLS) Parent Questionnaire assesses parental report of children's temperament on nine variables: Mood, distractibility, persistence, activity, rhythmicity, adaptability, approach-withdrawal, threshold and intensity. The present research was designed to assess the interrater reliability of this instrument and to provide cross-validation data regarding the nine scales. Questionnaires were validly completed by both parents of 47 children who had previously been evaluated at the Neuropsychology Laboratory of the Louisiana State University Medical Center. For each of the nine temperament variables, the scores obtained by each child when rated by his or her mother was significantly correlated with the score received on that variable when rated by the father. Thus, under the limitation imposed by the research design, it appears that parents are relatively consistent when evaluating the temperamental characteristics of their children. The correlations between each individual item and the factor it loads on were consistently highly significant. The nine temperamental variables are adequately assessed by the items included in the NYLS Questionnaire.

Effect of surface porosity on early thrombogenicity using vascular grafts with two surfaces in sequence

This experiment addresses the multifactorial dilemma of defining the ideal performance parameters of small internal diameter vascular grafts. We found silicone rubber vascular grafts with smooth surfaces remain acutely free of thrombotic deposits whereas grafts with rough surfaces promote a dispersed thrombus formation. This study also questions the concept that the thrombogenicity of one surface determines the thrombotic response of different and adjacent flow surfaces in the blood flow. Here the distinction between response to each surface was abruptly delineated and equal in intensity regardless of proximal or distal positioning. By studying the 2 surfaces in sequence, surface properties were evaluated using the minimal number of experiments by mitigating the effects of interanimal variability. This is an important consideration in an era of "cost accountability".

The use of bacteria as markers of leukemic lymphocytes and for the isolation of natural killer cells

Human lymphocyte subpopulations as well as leukemic lymphocytes can be identified and enumerated in blood smears by using bacteria that bind spontaneously to lymphocytes or by using bacteria to which antibodies are chemically coupled. The mechanism of natural binding of bacteria to lymphocytes was shown to involve a lectin on the lymphocyte surface and a carbohydrate on the bacteria. Also, we found that natural killer (NK) cells can be separated by negative selection using monolayers of bacteria. A subpopulation of T cells, identified by their binding of B. globigii, was shown to be suppressors for NK cells.

Case report. Clindamycin associated pseudomembranous colitis

Pseudomembranous colitis is rare in children. We describe a case associated with clindamycin in which Clostridium difficile and its enterotoxin were isolated from the stool. Treatment with oral vancomycin brought about a prompt and complete recovery.