Optical imaging of cell membrane potential changes induced by applied electric fields

We report the first imaging of the spatial distributions of transmembrane potential changes induced in nonexcitable cells by applied external electric fields. These changes are indicated by the fluorescence intensity of a charge-shift potentiometric dye incorporated in the cell plasma membrane and measured by digital intensified video microscopy.

Molecular counting of low-density lipoprotein particles as individuals and small clusters on cell surfaces

We employ the intensely fluorescent analogue diI-LDL (Barak, L. S., and W. W. Webb, 1981, J. Cell Biol. 90:595-604) as a counting marker to determine the numbers of LDL-receptor complexes that are contained in clusters on the surfaces of human fibroblasts and human epidermoid carcinoma cells. The application of quantitative digital intensified video optical microscopy allows the measurement of the fluorescence power collected from individual fluorescent spots on a cell with sufficient accuracy that the number of optically unresolved particles producing the fluorescence in the spot can be estimated. We demonstrate that isolated individual diI-LDL particles are detected on the surface of all cells investigated. Analysis of the LDL cluster size distributions on the various cell lines shows clear differences that correlate with efficiency of LDL metabolism. We find that normal fibroblasts (GM3348) have LDL-receptor complex populations dominated by large cluster sizes (greater than 4 LDL), while internalization-deficient J.D. mutant fibroblasts (GM2408A) and epidermoid carcinoma cells (A-431) show predominantly small clusters (1-3 LDL). No evidence for large-scale ordering or "superclustering" of clusters is found.

[The place of apatite in rheumatic diseases. Study of 25 cases by x-ray microanalysis and scanning electron microscopy]

The importance of "apatite deposition disease" among the arthropathies has been recognized for some years: it is well known that X-ray microanalysis (XRMA) is an efficient method of determining the elemental constitution of microcrystalline deposits obtained from synovial fluids or from tendon washing solutions during examination in scanning electron microscopy. In all 25 patients studied (11 intraarticular and 14 extraarticular samples), alizarine red S staining was positive and XRMA confirmed the diagnosis of apatite deposition by determination of the phosphorus/calcium (P/Ca) ratio in the deposits. In the 25 patients the mean values obtained for the P/Ca ratios were situated between 0.362 and 0.450, with a general mean value of 0.411, i.e. a ratio clearly lower than the P/Ca ratio of pure hydroxyapatite specimens (0.438) measured in identical conditions. This apparent discrepancy seems to be related to the probable presence of carbonated apatites. The study confirmed the presence of apatite microcrystals in intra- and extraarticular location; in the first condition, these were generally found in patients with severe destructive arthrosis, whereas in the second condition the calcifications derived from supraspinatus tendons.

Capillary orientation of rat pancreatic D-cell processes: evidence for endocrine release of somatostatin

We examined the ultrastructure of somatostatin-containing pancreatic D-cells in the rat in order to shed light on the function and mode of action of somatostatin in the pancreas. D-cells were first identified by indirect immunocytochemistry with the peroxidase-antiperoxidase technique on semithin (1-micron) sections of 2% glutaraldehyde-1.7% paraformaldehyde-fixed tissue from the tail of the pancreas. Fine ultrastructure of the positively identified D-cells was examined in adjacent sections (0.08 micron) by electron microscopy. D-cells characteristically exhibited long cytoplasmic projections that extended to capillaries. Each cell was divided arbitrarily into three zones of roughly equal size, nuclear, central, and capillary, and distribution of secretory granules into each zone was quantified. In unstimulated cells, secretory granules were dispersed throughout the D-cell. In sections obtained from rats stimulated to secrete somatostatin by infusion of 20 mM glucose-5 mM theophylline-20 mM L-arginine HCl, 75 +/- 4% of the D-cell granules was polarized to the capillary end of the cell, while only 54 +/- 2% was is this region in unstimulated rats (P less than 0.05). These studies suggest that pancreatic somatostatin is released into islet capillaries.

Treatment of active rheumatoid arthritis with slow intravenous injections of thymopentin. A double-blind placebo-controlled randomised study

41 patients with active rheumatoid arthritis entered a placebo-controlled double-blind randomised study in which 21 received slow intravenous injections (given in fractions over 10 min) of thymopentin (TP-5) 50 mg 3 times a week for 3 consecutive weeks and 20 received placebo in the same way. After 3 weeks of treatment the TP-5 group showed improvement (p less than 0.05 or p less than 0.01) in all but one of the clinical variables tested. There was improvement in the number of joints painful at rest, the number of joints painful on motion, scores for tenderness on pressure and swollen joints, severity of pain on awakening and morning stiffness, and right-hand grip strength; left-hand grip strength remained unchanged. In the placebo group, only morning stiffness improved significantly. The intergroup comparisons showed that thymopentin was significantly better than placebo in reducing tenderness, joint swelling, severity of pain on awakening, and disease activity. 4 weeks after the end of the TP-5 therapy, the improvement was still present although there was a trend towards relapses. No significant modifications occurred in any of the laboratory variables tested and only minor side-effects were experienced by either group.

Peripheral mucociliary clearance with high-frequency chest wall compression

We investigated the effects of high-frequency chest wall compression (HFCWC) on peripheral and tracheal mucus clearance in anesthetized spontaneously breathing dogs. HFCWC was achieved by oscillating the pressure in a thoracic cuff with a piston pump. Regional lung retention of a technetium-99m sulfur colloid aerosol was monitored with a gamma camera. A peripheral mucus clearance index (PMCI) was defined for each region of interest. The tracheal mucus clearance rate (TMCR) was determined by bronchoscopic visualization of marker particle transport. Phase I: In seven dogs, 30 min of HFCWC at 13 Hz with peak cuff pressure (Pcuff) 100-120 cmH2O was found to significantly enhance PMCI in regions immediately under the cuff. (delta PMCI = 24.4 +/- 4.6 in the basal peripheral region.) Phase II: Because of subpleural hemorrhage in phase I, the effect of HFCWC on TMCR at various Pcuff levels was studied in five dogs. The enhancement of TMCR by HFCWC reached a plateau level at Pcuff = 50 cmH2O. Phase III: HFCWC at 13 Hz with Pcuff = 50-60 cmH2O was found to significantly enhance PMCI in five dogs without the consequence of hemorrhage. Correlations were found between the enhancement of PMCI and TMCR by HFCWC. These results demonstrate that HFCWC is effective in enhancing both peripheral and central mucus clearance in dogs and safe when moderate pressures are applied.

Confirmative study of the effectiveness of thymopentin in active rheumatoid arthritis

Forty-one patients with active rheumatoid arthritis entered a controlled double-blind randomized study. Of these patients, 21 received prolonged intravenous injections (10 min) of thymopentin 50 mg three times a week for 3 consecutive weeks, whereas 20 received placebo. Both groups were comparable with regard to clinical parameters. No immunological tests were performed. Analysis of the results after 3 weeks showed that the improvement in the thymopentin group was statistically significant (p less than 0.05 or p less than 0.01) for all clinical parameters, except for the left-hand grip strength. On the other hand, no significant improvement was observed for any parameter, except morning stiffness, in the patients on placebo. The intergroup comparison showed statistically significant differences, favoring thymopentin over placebo treatment, in the Ritchie index, the scores of swollen joints, the assessment of severity of pain, and the scores for changes in the activity of the disease. The present placebo-controlled double blind study thus confirms the positive results generated in a similar open study, i.e., the beneficial therapeutic effect of prolonged intravenous injections of thymopentin in patients with severe rheumatoid arthritis. The drug appears to be safe at the dose regimen used.

High frequency chest wall compression and carbon dioxide elimination in obstructed dogs

High frequency chest wall compression (HFCWC) was studied as a method of assisting ventilation in six spontaneously breathing anesthetized dogs. Under a constant level of anesthesia, the dogs became hypercapneic after airflow obstruction was created by metal beads inserted in the airways. HFCWC was achieved by a piston pump rapidly oscillating the pressure in a modified double blood pressure cuff wrapped around the lower thorax. Thirty minute periods of spontaneous ventilation were alternated with thirty minute periods of spontaneous breathing plus HFCWC at 3, 5 or 8 Hz. The superimposition of HFCWC to spontaneous ventilation resulted in little change in the PaO2. The PaCO2, however, was reduced in every case from a mean of 6.55 +/- 0.59 to 4.72 +/- 0.32 kPa at 3 Hz (p less than 0.05), 6.92 +/- 0.57 to 3.9 +/- 0.45 kPa at 5 Hz (p less than 0.01) and 7.10 +/- 0.65 to 4.56 +/- 0.59 kPa at 8 Hz (p less than 0.05). This occurred despite a decrease in spontaneous minute ventilation. We conclude that HFCWC can assist in elimination of CO2 in obstructed spontaneous breathing dogs with hypercapnea.

Effects of somatostatin on food intake in rats

We examined the possibility that somatostatin, a tetradecapeptide distributed in the gut and the central nervous system, may influence food intake and behavior in rats. Although intravenously infused somatostatin did not alter food intake in 8 hour fasted rats, intracerebroventricularly infused somatostatin resulted in a biphasic response, first increasing then decreasing food intake. We also observed that the effects of somatostatin vary depending upon whether animals are fed or fasted. In fed rats, food intake was decreased, while in fasted rats food intake was increased. These results suggest that somatostatin can act in the central nervous system to stimulate appetite; but that other factors, possibly related to gut motility or clearance, may inhibit further feeding once the stomach is full.

Surface antigens of melanoma and melanocytes. Specificity of induction of Ia antigens by human gamma-interferon

IFN-gamma is known to induce expression of Ia antigens on a variety of cell types. In the present study, this activity of IFN-gamma has been analyzed with a panel of 36 melanoma cell lines, normal melanocytes, and 97 cell lines representing a range of other differentiation lineages. 55% of the melanoma cell lines express Ia antigens in a constitutive manner without IFN-gamma induction. Of the 16 Ia-melanoma lines, 13 could be induced to express Ia antigens by IFN-gamma, whereas three were noninducible. Melanocytes, which do not normally express Ia antigens, are converted to Ia expression by IFN-gamma. Ia antigens expressed constitutively or after IFN-gamma induction were identified with antibodies detecting monomorphic and allomorphic products of DR and DC loci. IFN-gamma appeared to be unique in its ability to induce Ia expression on melanoma and melanocytes; 14 other agents (including IFN-alpha and IFN-beta) known to influence growth or differentiation did not have Ia-inducing activity. Equally striking is the restriction of antigenic changes following IFN-gamma induction to HLA-associated products; of the 38 systems of cell surface antigens examined, only HLA-A,B,C, beta 2m, and Ia antigens were affected. A variety of other Ia- cell types were shown to be Ia-inducible by IFN-gamma; these included established lines of breast, colon, pancreas, bladder, kidney, ovary, and brain cancers, and cultures of normal fibroblasts, kidney epithelia, and epidermal keratinocytes. In contrast, three tumor types, teratocarcinoma, choriocarcinoma, and neuroblastoma, were not inducible for Ia expression, even though IFN-gamma could induce expression of HLA-A,B,C products. The broad representation of Ia antigens on most somatic cell types expressed either constitutively or after IFN-gamma can be viewed in an immunological context (antigen presentation/immune regulatory signals) or could indicate that Ia products have functions other than those related to immune reactions.

[Contralateral local anesthesia in stump, phantom and post-traumatic pain]

Contralateral local anaesthesia was employed in patients with chronic (n = 42) and acute (n = 8) pain syndromes (see Table 1). I. Phantom limb and stump pain: n = 10; II. Pain of face and ear: n = 10; III. Pain of neck and trunk: n = 14; IV. Pain of the hip joint: n = 6; V. Pain of the extremities: n = 10: Sa. = 50 patients. Among these were n acute pain syndromes: I.: n = 0; II.: n = 1; III.: n = 1; IV.: n = 1; V.: n = 5 (Sa.: n = 8). 42 patients with chronic pain syndromes were treated with contralateral local anaesthesia (CLA). In 27 patients CLA displayed a clear effect upon the chronic pain; in 8 patients pain release was more than 50%, in 15 patients pain release was less than 50%. 3 patients relapsed into their former condition of pain. CLA was without any positive influence in 12 cases. The medium frequency of treatments was between 5 and 6 in both groups. The average time of treatment amounted to 6 and 7 months respectively. In 8 patients with acute pain syndromes contralateral local anaesthesia produced the following results: 6 patients were permanently released from their pain; in 2 patients CLA remained without any success. The average frequency of treatment was 1.25; the average time of observation was 2.3 months. Hence we suggest that CLA should be employed as early as possible in acute or chronic posttraumatic or postoperative pain syndromes. The influence of contralateral pain therapy on acute and chronic pain conditions of the opposite side can be affirmed; its mechanism remains to be clarified. Obviously it is possible to exert an inhibitory influence from the contralateral side upon peripheral, spinal, reticular and thalamic regions, which can lead to the extinction of acute and chronic pain conditions on the opposite side. According to our experiences it is necessary that the cerebro-spinal nerve system - apart from the traumatic lesion - is intact and that the pain syndrome is not maintained by a psychic disturbance.

Effect of food-deprivation on rat pancreatic islet cells

Somatostatin, insulin and glucagon concentrations in rat pancreas were measured following various intervals of food-deprivation. Tissue concentrations, as measured by radioimmunoassay, were correlated with A-, B-, and D-cell number and size using a scanning integrating image analyzer (Quantimet 720). Alterations in total islet hormone content were not correlated to changes in size or distribution of cells. This implies that changes in tissue content reflect changes in turnover of peptides rather than changes in cell size or number.

Enhanced tracheal mucus clearance with high frequency chest wall compression

The clearance of mucus in the trachea during high frequency chest wall compression (HFCWC) was studied in nine anesthetized dogs. High frequency chest wall compression was applied by oscillating the pressure in a thoracic cuff such that it produced oscillatory tidal volumes of 25 to 100 cc at frequencies of 3 to 17 Hz. The tracheal mucus clearance rate (TMCR) was determined by direct observation of the rate of displacement of a charcoal particle spot by means of a fiberoptic bronchoscope. Baseline TMCR during spontaneous breathing averaged 8.2 +/- 5.6 mm/min in the 9 dogs. The TMCR during 2 min of HFCWC was increased at 5, 8, 11, 13, 15, and 17 Hz but not at 3 Hz. The enhancement of clearance was most pronounced in the range of 11 to 15 Hz, reaching a peak value of 340% of control at 13 Hz. These studies suggest that HFCWC might be of considerable potential benefit as a mode of chest physiotherapy.

Animal model of isolated gonadotropin deficiency. II. Morphologic responses to LHRH immunoneutralization

Morphologic changes in the male reproductive system of mongrel dogs immunized against LHRH were quantitated using linear measurements and morphometric techniques at the light-microscopic level. Two experimental groups (5 nonimmunized control animals and 5 actively immunized animals) were killed 12 weeks after the primary immunization. No significant differences were observed between three immunized dogs having low LHRH antibody titers (immunized-unaffected) and the five nonimmunized control dogs. The two immunized dogs (affected) with the highest antibody titers against LHRH were characterized by atrophy and dedifferentiation of the testes, prostate, and excurrent ducts. The morphologic changes in the testes of these two dogs were striking and included an apparent arrest or significant reduction in the spermatogenic process, concurrent epithelial degeneration, and apparent diminution of Leydig cell mass. Drastic reductions in the size of the prostatic acini and epithelial cells, as well as loss of secretory granules, reflected depression of function and androgen production. Similarly, in the excurrent ducts decreases in the measured parameters and loss of regional cytoplasmic specialization denoted functional decrescence. This study demonstrates the regressive effects of LHRH immunoneutralization on the morphology of the reproductive system in the male dog and further supports the feasibility of this system as an animal model for the study of isolated gonadotropin deficiency.

Animal model of isolated gonadotropin deficiency. I. Hormonal responses to LHRH immunoneutralization

Five intact male mongrel dogs, characterized by an episodic secretory pattern of LH and normal serum testosterone concentrations, were actively immunized against LHRH by subcutaneous injections of 200 micrograms of a LHRH-human serum albumin conjugate at 0, 4, and 8 weeks. After 12 weeks, two dogs having the highest antibody titers to LHRH (25% and 51% binding of 125I-LHRH in serum diluted 1:1000 B/Bo) had low to nondetectable serum concentrations of LH and testosterone, whereas serum FSH concentrations were significantly reduced in only one of these dogs. Immunocytochemical techniques showed that the pituitaries of these same two dogs had smaller and fewer LH immunoreactive gonadotropes than did the pituitaries of another three immunized-nonaffected dogs or of the five nonimmunized control dogs. The two LHRH-immunized dogs characterized by hypogonadotropism also had reduced testis (4.0 and 4.0 g) and prostate (2.1 and 1.7 g) weights when compared to control dogs (testis: 12.1 +/- 1.0 g and prostate: 9.2 +/- 1.9 g). LHRH antibody titers in three immunized dogs were demonstrable (8.1, 9.8, and 14.2% B/Bo), but effects on LH, FSH, and testosterone concentrations, pituitary gonadotropes, and reproductive tissue weights were not apparent. The similarity in hormonal and tissue responses observed between dogs effectively immunized against LHRH and men with isolated gonadotropin deficiency suggests that the LHRH-immunized dog may provide a suitable experimental model for the study of patients with isolated gonadotropin deficiency.

Theory of electromechanical effects in nerve

The electromechanical transduction mechanisms operating in nerve membranes are considered theoretically. For mechanical-to-electrical transduction (mechanical generator potentials), a model is proposed in which the surface charge on the membrane mediates stress-induced changes in the intramembrane electric field, thus opening transmembrane ion conductance channels or reducing the ion selectivity of the membrane via leak conductance pathways. For electrical-to-mechanical transduction (axon diameter change with excitation), an investigation into two well-known electrostatic properties of dielectrics, electrostriction and piezoelectricity, in the context of the nerve membrane is undertaken which predicts a few percent change in axon dimensions for voltage- and space-clamped axons.

Ventilation by high-frequency chest wall compression in dogs with normal lungs

In 6 anesthetized and paralyzed supine dogs, ventilation by high-frequency chest wall compression (HFCWC) was accomplished by a piston pump rapidly oscillating the pressure in a modified double blood pressure cuff wrapped around the lower thorax. Testing applied frequencies at 3, 5, 8, and 11 Hz, applied peak cuff pressures ranged from 30 to 230 cmH2O. This produced swings of esophageal pressure as high as 18 cmH2O and peak oscillatory air flow ranging from 0.7 to 1.6 L/s. Oscillatory tidal volume declined with increasing frequency and ranged from a mean of 61 to 45 ml. After 30 min of applied HFCWC, arterial blood gas determinations revealed a mean PaCO2 of 29.3 mmHg at 5 Hz, 35 mmHg at 3 Hz, 36 mmHg at 8 Hz, and 51 mmHg at 11 Hz. Mean PaO2 improved from ventilator control values at 3 Hz, remained unchanged at 5 and 8 Hz, and declined at 11 Hz. In 2 dogs breathing spontaneously, HFCWC applied at 5 and 11 Hz resulted in a reduction in spontaneous minute ventilation, mainly by a reduction in spontaneous tidal volume, whereas arterial blood gas values changed slightly. One dog ceased to breath spontaneously within 5 min of application of HFCWC as the PaCO2 fell below control values. We conclude that in dogs with normal lungs, HFCWC may assist spontaneous ventilation. In paralyzed dogs, HFCWC may be of sufficient magnitude to cause hyperventilation.

Antihypertensive beta-adrenergic blocking agents: N-aralkyl analogues of 2-[3-(tert-butylamino)-2-hydroxypropoxy]-3-cyanopyridine

An interest in dual-acting antihypertensive agents, specifically those related to (S)-2-[3-(tert-butylamino)-2-hydroxypropoxy]-3-cyanopyridine (1), led us to probe the contribution of the side-chain amino substituent in this series. The ability of 1 and its various analogues to displace radiolabeled alpha 1 (WB-4101 and prazosin) and beta (dihydroalprenolol) adrenergic receptor ligands was assessed by receptor-binding techniques. Most of the compounds exhibited high beta-adrenoceptor binding affinities, but only the N-aralkylamino-substituted compounds showed high alpha 1-adrenoceptor affinities. Therefore, the vasodilation shown by 1 was not due to an interaction with the alpha 1 adrenoceptor. The aralkylamino analogues of 1 in spontaneously hypertensive rats and anesthetized dogs exhibited antihypertensive activity and alpha 1-adrenoceptor blocking properties. Unlike the preference shown by beta-adrenoceptors for S enantiomers in this oxymethylene class of beta blockers, the chirality at the secondary hydroxy center made only a minor contribution to the affinity for the alpha 1-adrenoceptor and even less of a contribution to the observed antihypertensive effects. This lack of chiral influence at the hydroxy center confirmed what had been previously observed in more limited studies with the isomers of both labetalol and medroxalol.