Two-dimensional (crossed) immunoelectrophoresis

Two-dimensional (2-D) immunoelectrophoresis, also known as crossed immunoelectrophoresis, is a particularly useful technique for the quantitation of mixtures of proteins and the analysis of the composition of protein mixtures. The method consists of two sequential electrophoretic steps: 1. The first dimension, during which the protein mixture to be analyzed is separated by electrophoresis in an agarose gel. 2. The second dimension, during which the separated proteins are electrophoresed at right angles into a freshly applied layer of agarose containing a predetermined amount of antibody.

Detection of protein blots using enzyme-linked second antibodies or protein a

The immunodetection of a specific protein on a protein blot relies initially on the ability of a primary antibody to bind specifically to the protein of interest. This is simply achieved by washing the nitrocellulose paper in a dilute solution of the antibody. Before this step is carried out, however, unblocked protein binding sites on the nitrocellulose paper must be masked by washing with a general blocking solution (e.g., bovine serum albumin solution, dilute bovine serum, gelatin solution, hemoglobin solution, and so on). In this way, nonspecific binding of the antibody (which is itself a protein) to nitrocellulose is prevented, and any antibody that does bind to the paper will be doing so by a genuine antigen-antibody reaction alone. This antigen-antibody reaction must now be visualized. This can be achieved by washing the paper with an appropriately labeled ligand that binds specifically to the primary antibody. This ligand is generally of two possible types: 1. Protein A (which binds specifically to IgG molecules) either radiolabeled or linked to a marker enzyme (see below). 2. A second antibody (anti-IgG) that binds to the primary antibody. This second antibody is used linked to a marker enzyme. Alternatively this second antibody is linked to biotin. This biotinylated antibody is then treated with avidin linked to a marker enzyme (avidin binds with high specificity to biotin).

Air-fluidized beds or conventional therapy for pressure sores. A randomized trial

STUDY OBJECTIVE

To compare the effectiveness and adverse effects of air-fluidized beds and conventional therapy for patients with pressure sores.

DESIGN

Randomized trial with both masked and unmasked comparisons of outcome after a median follow-up of 13 days (range, 4 to 77 days).

SETTING

Urban, academic referral, and primary care medical center.

PATIENTS

Of 140 potentially eligible hospitalized patients with pressure sores, 72 consented to randomization; 65 (90%) completed the study.

INTERVENTIONS

Thirty-one patients on air-fluidized beds (Clinitron Therapy, Support Systems International, Inc., Charleston, South Carolina) repositioned every 4 hours from 0700h to 2300h without use of other antipressure devices. Thirty-four patients on conventional therapy used an alternating air-mattress covered by a foam pad (Lapidus Air Float System, American Pharmaceal Company, Cincinnati, Ohio) on a regular hospital bed; were repositioned every 2 hours; and had elbow or heel pads as needed. Topical therapy was standardized for both groups.

MEASUREMENTS AND MAIN RESULTS

Pressure sores showed a median decrease in total surface area (-1.2 cm2) on air-fluidized beds, but showed a median increase (+ 0.5 cm2) on conventional therapy; 95% confidence interval (CI) for the difference between medians, -9.2 to -0.6 cm2 (p = 0.01). Improvement, as assessed from serial color photographs by investigators masked to treatment group, occurred in 71% and 47%, respectively; 95% CI for the difference, 1% to 47% (p = 0.05). For pressure sores 7.8 cm2 or greater, outcome differences between air-fluidized beds and conventional therapy were greater: median total surface area change was -5.3 and +4.0 cm2, respectively; 95% CI for the difference, -42.2 to -3.2 cm2 (p = 0.01). Improvement rates were 62% and 29% respectively; 95% CI for difference, 1% to 65% (p = 0.05). After adjusting for other factors associated with sore outcome, the estimated relative odds of showing improvement with air-fluidized beds were 5.6-fold (95% CI, 1.4 to 21.7) greater than with conventional therapy (p = 0.01). No significant increase in adverse effects was seen with air-fluidized beds.

CONCLUSIONS

Our findings suggest that air-fluidized beds are more effective than conventional therapy, particularly for large pressure sores. Studies are needed to determine the effectiveness of air-fluidized beds in long-term care settings.

Mu-opiate binding and morphine antagonism by octapeptide analogs of somatostatin

A series of cyclic conformationally restrained octapeptide analogs of somatostatin were examined for their ability to inhibit the binding of tritiated mu, kappa, and delta opiate receptor ligands. Several of these substances were found to have high affinity for mu opiate receptors while having very low affinity for both kappa and delta receptors. Previous suggestions that somatostatin analogs exhibit opiate antagonist activity led to a study of the ability of the two most potent compounds to inhibit morphine analgesia in rats after intracerebroventricular injection. One of the compounds significantly antagonized morphine analgesia although the other displayed severe toxicity. These two compounds differed in that the very toxic compound had previously been found to possess significant somatostatin activity. It thus appears that the structural requirements for toxicity and somatostatin activity can be differentiated from those for opiate activity.

Effects of dynorphin (1-8) on movement: non-opiate effects and structure-activity relationship

Cell bodies in the head of the caudate nucleus that synthesize prodynorphin peptides form a substantial projection to the substantia nigra pars reticulata (SNR). The discovery of this pathway suggested an involvement of prodynorphin products in motor control. The effects of unilateral nigral microinjections of prodynorphin products were tested in an in vivo circling model. Dynorphin (1-8), dynorphin (1-7), dynorphin (1-6), dynorphin (2-17) (des-Tyr-dynorphin), and Leu-enkephalin induced spontaneous contralateral circling at 20 nmol doses. The effect of dynorphin (1-8) was dose dependent and was not blocked by pretreatment with naloxone or WIN 44,441-3. These findings clearly demonstrate the dynorphinergic involvement in nigral motor control which may consist of an opioid and a non-opioid component.

[D-Ala2, (F5) Phe4]-dynorphin 1-13-NH2 (DAFPHEDYN): a potent analog of dynorphin 1-13

Intracerebroventricular administration of the dynorphin analog, [D-Ala2,(F5)Phe4]-dynorphin 1-13-NH2 (DAFPHEDYN) in rats produced diuresis and profound analgesia. Both effects were antagonized by central administration of naltrexone or naloxone. Intravenous administration of 10, 25, and 50 mg/kg of DAFPHEDYN failed to induce diuresis. The increased potency of DAFPHEDYN was apparent from the failure of an equal dose of the parent compound (dynorphin 1-13) to produce diuresis and the failure of [D-Ala2]-dynorphin 1-13-NH2 to produce analgesia. Radioligand binding studies indicated the DAFPHEDYN retains the same degree of kappa selectivity as the parent compound (dynorphin 1-13) though a drop in affinity occurred. DAFPHEDYN may be of significant interest because it retains the essential pharmacology of the parent compound and exhibits marked in vivo potency.

Microalgae and cyanobacteria as a source of glycosidase inhibitors

Culture filtrates and organic solvent extracts of over 500 freshwater and marine eukaryotic microalgae and cyanobacteria were screened for the presence of glycosidase inhibitors. Rapid colorimetric assays were used to detect inhibitors of alpha-glucosidase, alpha-amylase and beta-galactosidase. Inhibitors were found from 38 species. The results suggest that microalgae and cyanobacteria have potential as a source of glycosidase inhibitors which may have clinical applications.

The degradation of dynorphin A in brain tissue in vivo and in vitro

The demonstration of analgesia following in vivo administration of dynorphin A (Dyn A) has been difficult. In contrast, a number of electrophysiological and behavioral effects reported with in vivo injection of Dyn A can be produced by des-tyrosine dynorphin A (Dyn A 2-17). This suggested the extremely rapid amino terminal degradation of dynorphin A. To test this hypothesis, we examined the degradation of dynorphin A following in vivo injection into the periaqueductal gray (PAG) as well as in vitro using rat brain membranes under receptor binding conditions. In vivo, we observed the rapid amino terminal cleavage of tyrosine to yield the relatively more stable destyrosine dynorphin A. This same cleavage after tyrosine was observed in vitro. Inhibition of this aminopeptidase activity in vitro was observed by the addition of dynorphin A 2-17 or dynorphin A 7-17 but not after the addition of dynorphin A 1-13, dynorphin A 1-8, dynorphin B or alpha-neo-endorphin suggesting a specific enzyme may be responsible. The detection of the behaviorally active des-tyrosine dynorphin A following in vivo injection of dynorphin A suggests that this peptide may play an important physiological role.

Opposite effects of mu and kappa opiates on the firing-rate of dopamine cells in the substantia nigra of the rat

Single unit extracellular recording was carried out in rats to compare the actions of a mu receptor agonist (morphine) to a kappa receptor agonist (U50,488) in the substantia nigra pars compacta (SNC). Intravenously administered morphine and U50,488 exhibited opposite effects: morphine excited SNC dopamine cells, and U50,488 inhibited them. Both effects were blocked by naloxone, although significantly more naloxone was necessary to block the effect of the kappa agonist. Local administration of U50,488 in the caudate also inhibited the firing of SNC dopamine cells. These results are discussed in terms of the natural functions of the prodynorphinergic straiatonigral projection.

Pressure sores among hospitalized patients

A cross-sectional survey was done to determine the prevalence of pressure sores in hospitalized patients and the factors associated with having a pressure sore in the hospital. Among 634 adult patients, 30 (4.7%; 3.1% to 6.3%, 95% confidence interval) had a pressure sore and 78 (12.3%; 9.8% to 14.8%) were at risk for a pressure sore because they had been confined to a bed or chair for at least 1 week. Comparing these two groups of patients, we found that fecal incontinence, diarrhea, fractures, urinary catheter use, decreased weight, dementia, and hypoalbuminemia were associated with having pressure sores (p less than or equal to 0.05). Using logistic regression analysis, hypoalbuminemia, fecal incontinence, and fractures remained significantly and independently associated with having a pressure sore (odds ratios = 3.0, 3.1, and 5.2, respectively; p less than or equal to 0.05). Our findings suggest that 17% (14% to 20%) of hospitalized patients have pressure sores or are at risk for them, and that hypoalbuminemia, fecal incontinence, and fractures may identify bedridden patients at greatest risk.

Thermoregulation, metabolism, and stages of sleep in cold-exposed men

Four naked men, selected for their ability to sleep in the cold, were exposed to an ambient temperature (Ta) of 21 degrees C for five consecutive nights. Electrophysiological stages of sleep, O2 consumption (VO2), and skin (Tsk), rectal (Tre), and tympanic (Tty) temperatures were recorded. Compared with five nights at a thermoneutral Ta of 29 degrees C, cold induced increased wakefulness and decreased stage 2 sleep, without significantly affecting other stages. Tre and Tty declined during each condition. The decrease in Tre was greater at 21 degrees C than at 29 degrees C, whereas Tty did not differ significantly between conditions. Increases in Tty following REM sleep onset at 21 degrees C were negatively correlated with absolute Tty. VO2 and forehead Tsk also increased during REM sleep at both TaS, whereas Tsk of the limb extremities declined at 21 degrees C. Unsuppressed REM sleep in association with peripheral vasoconstriction and increased Tty and VO2 in cold-exposed humans, do not signify an inhibition of thermoregulation during this sleep stage as has been observed in other mammals.

Ear oximetry to detect apnea and differentiate rapid eye movement (REM) and non-REM (NREM) sleep. Screening for the sleep apnea syndrome

Ear oximetry is commonly employed in screening patients for the sleep apnea syndrome, but the lack of objective information regarding the duration of sleep, including the presence of rapid-eye-movement (REM) sleep, is a major limitation. Based on the premise that both apnea and sleep-state-dependent changes in ventilation give rise to distinctive patterns in the arterial oxygen saturation, we developed a systematic technique to analyze ear oximetric tracings for wakefulness, REM sleep, and non-REM (NREM) sleep. Fifty-four patients were studied by both all-night polysomnography and ear oximetry. A careful comparison of ear oximetric data for sleep states and apnea was then made, using polysomnography as the correct classification to determine sensitivity, specificity, predictive value positive, and predictive value negative of the ear oximetric tracings. When classification of sleep state was compared, ear oximetry correctly classified 280.5 (82 percent) of 340.9 hours of sleep that was either REM or NREM sleep. The sensitivity for classifying NREM sleep was 0.85, for REM sleep was 0.70, and for wakefulness was 0.49. The sensitivity by ear oximetry for apnea was 0.80, with a predictive value negative of 0.87. We conclude that although polysomnography must be performed for definitive evaluation, ear oximetry is a valuable screening test for sleep apnea because the presence or absence of apnea can be determined, total duration of sleep can be estimated, and NREM vs REM sleep can be differentiated.

[3H]dynorphin A binding and kappa selectivity of prodynorphin peptides in rat, guinea-pig and monkey brain

We have previously demonstrated that [3H]dynorphin A selectively labels kappa opioid receptors in guinea-pig whole brain. In these current studies, using protection from inactivation by beta-chloronaltrexamine (beta-CNA), we are able to demonstrate that although dynorphin A prefers kappa receptors, it will label mu receptors when kappa receptors are not available, or present in only a small number. Thus, differences in numbers of mu and kappa receptors present in brain preparations are critical in determining the receptor binding profile of [3H]dynorphin A across species. Additionally, although all the prodynorphin derived peptides show kappa preference, the ability of the other prodynorphin derived peptides to compete with [3H]dynorphin A for its receptor varies across species. Consequently, in a highly enriched kappa preparation such as monkey cerebral cortex, [3H]dynorphin A appears to label kappa receptors with substantial selectivity, and the other prodynorphin-derived peptides show less ability to compete with dynorphin A for its receptor. In contrast, in a kappa-poor tissue such as rat brain, all of the prodynorphin-derived peptides, including dynorphin A-(1-8), show very similar potency. Thus, differences in mu and kappa receptor numbers across brain regions and species lead to differences in the receptor binding profile of dynorphin A.

Lack of difference between malignant and accelerated hypertension

The clinical features and survival rates of 200 consecutive patients with malignant and accelerated hypertension admitted to a district hospital were investigated. Ninety five patients had bilateral haemorrhages and exudates and papilloedema (grade IV retinopathy) and 31 had bilateral haemorrhages and exudates with no papilloedema (grade III). A further 74 patients had bilateral retinopathy but failed to meet the criteria for grade IV or III and were investigated separately. No overall differences were found in survival when comparing the various grades of retinopathy. Cigarette smoking was significantly commoner only in grade IV patients compared with those with non-malignant hypertension matched for age, sex, and race. In patients with grade III retinopathy excess smoking was not statistically significant. In conclusion, the clinical features and survival rate showed that malignant and accelerated hypertension are one and the same disease.

Evaluation of a coronary lysing system: results of a preclinical safety and efficacy study

The purpose of this study was to evaluate the efficacy and safety of a recently developed transluminal lysing system in the removal of coronary stenotic lesions from a human cadaver heart and in the cannulation of coronaries in the anesthetized dog. The left coronary arteries of three dogs were cannulated on separate occasions, with coronary arteriography and translation of the transluminal lysing system cutter to the distal segments of the coronary vessels performed each time. Proximal and distal coronary pressures were recorded from the guiding catheter and the transluminal lysing system cutter, demonstrating no significant pressure differential and minimal damping. Pathological examination of the dog coronaries after sacrifice demonstrated minor intimal irregularities with no significant thrombosis or vessel perforation. A significant portion of the occlusive stenotic lesions were removed from coronary vessels of a human cadaver heart with subsequent reestablishment of angiographic dye flow to the distal coronary vessels without evidence of debris loss from the transluminal lysing system cutter or the appearance of occlusions in the distal vessels. We conclude that the transluminal lysing system can be introduced into the coronary artery of a living dog on repeated occasions without causing significant coronary damage, coronary occlusive thrombosis, myocardial destruction, morbidity, or mortality; furthermore, occlusive stenotic lesions can be removed from cadaver coronary vessels by the transluminal lysing system with the establishment of angiography patency.

Cigarette smoking, blood pressure and the control of blood glucose in the development of diabetic retinopathy

We have investigated the relationship between diabetic retinopathy and cigarette smoking, blood pressure, control of blood glucose, duration of diabetes and insulin requirement in a cross sectional study of 193 adult patients attending 2 diabetic follow-up clinics. Multiple discriminate analysis demonstrated that the duration of diabetes was closely related to the development of retinopathy in both sexes. Cigarette smoking was related to retinopathy in men but not in women, although in that group the prevalence of smoking was low. The average blood glucose whilst attending the clinic was weakly related to retinopathy in men only whereas the presence of hypertension was weakly related in women only. Cigarette smoking in men at least may be an aggravating factor for diabetic retinopathy.

Effects of intracoronary and intravenous amrinone infusions in patients with cardiac failure and patients with near normal cardiac function

The effects of intracoronary and intravenous infusions of amrinone were studied to distinguish the drug's direct cardiac actions from its peripheral vascular and neuroendocrine properties. Intracoronary infusions of amrinone were found to have no haemodynamic effect other than producing a slight reduction in the left ventricular ejection fraction and some suggestion of coronary vasodilatation in patients with impaired left ventricular function. They did not improve contractility, cardiac output, or filling pressures and had no significant effect on myocardial metabolism, although therapeutic concentrations of the drug were detected in coronary sinus blood. Intravenously administered amrinone reduced filling pressures and improved the cardiac index in all patients, but haemodynamic improvements were most pronounced in the patients with the worst cardiac function. These changes were accompanied by improvements in the indices of contractility only in patients in whom alterations in concentrations of free fatty acid, glycerol, and glucose suggested peripheral catecholamine release. In the patients with the best basal cardiac function intravenously administered amrinone produced a reduction in myocardial work and evidence of myocardial ischaemia, as a result of excessive reduction of coronary perfusion pressure and increased heart rate, without any appreciable increase in cardiac index. It is concluded that, at the concentrations of the drug that can be achieved in man without adverse effects, amrinone has no direct positive inotropic effect. Haemodynamic changes are predominantly the result of vasodilatation, although catecholamines may be released in some patients.

Electrophysiological effects of dynorphin peptides on hippocampal pyramidal cells in rat

Single-unit extracellular recording was carried out in rats to characterize the effects of dynorphin and several structurally related peptides on hippocampal pyramidal cell activity. Dynorphin, applied electrophoretically or by pneumatic pressure, produced a dose-dependent depression of both spontaneous and glutamate-evoked discharge in a majority (63%) of CA1 and CA3 cells tested. In addition, a small number of cells in both cellular fields responded to the peptide with a prolonged elevation in firing. The inhibitory effects of dynorphin were not blocked by naloxone. Moreover, administration of des-tyrosine-dynorphin depressed the firing of pyramidal cells in a manner similar to that of the parent compound. Ethylketocyclazocine produced a mixed pattern of excitatory and inhibitory effects, whereas naloxone-sensitive elevations in firing were most often observed with the application of dynorphin-(1-8). Application of [Leu5]enkephalin produced only facilitations in pyramidal cell firing. The possibility is raised that biologically significant non-opiate actions, in addition to potent opiate-mediated effects, may occur upon release of pro-dynorphin peptides in the hippocampus.

Rising from a chair. Influence of age and chair design

We studied the effect of age on the act of rising from a standard armchair in a younger (means = 24 years) and an older (means = 75 years) group of healthy adult women. Rising from a standard armchair and an armchair specially designed for comfort in sitting of the elderly was studied in the older group to determine the influence of the special chair. We used electrogoniometry, EMG, and videotape analysis to record the activity for both groups. The older group placed their feet farther back and showed greater vastus lateralis muscle activity than did the younger group to rise from the standard chair. These results suggest that rising from the standard chair was more difficult for the older than for the younger group. In the special chair, the older subjects showed even more vastus lateralis muscle activity, greater knee flexion, and greater trunk forward lean. Rising from the special chair, therefore, appeared to be more difficult than rising from a standard chair; this finding suggests that both comfort and function must be considered in chair selection for certain groups.

Relationships between beat-to-beat interval and the strength of contraction in the healthy and diseased human heart

Twenty-six adult patients, classified by clinical and catheter criteria into groups of those with normal and abnormal left ventricular function, were studied during cardiac catheterization. Right heart pacing was established, and left ventricular dP/dt was measured with end-catheter manometers. By varying the interval preceding a test beat after periods of steady pacing it was confirmed that recovery of left ventricular mechanical function (maximum dP/dt) occurs approximately 800 msec (optimum interval) after a beat. The augmentation of maximum dP/dt of the first 2 beats after an extrasystole, each spaced at the optimum interval, was also studied; the amount of potentiation was varied by alterations in extrasystolic interval. Potentiation decayed from the first to the second postextrasystolic beat with a ratio that was fixed in each individual patient. The ratio (recirculation fraction) was higher in patients with normal than in those with abnormal left ventricular function (mean +/- SD 0.52 +/- 0.10 vs 0.37 +/- 0.11, p less than .005). There was an inverse relationship between this ratio and the degree of potentiation of the first postextrasystolic beat (r = .80, p less than .001). We postulate a disturbance of excitation-contraction coupling mechanisms to explain these effects.

Chromatin associated protease from calf thymus

We have identified and purified a chromatin bound protease from calf thymus. The purified enzyme cleaves histone H1 when whole histone is used as substrate. The enzyme is inhibited by Soya bean trypsin inhibitor, but not by PMSF, EDTA, pepstatin or Ellman's reagent. Further studies have shown that H1(0) and histone H5 are also cleaved by this enzyme, and that when HMG 1 and 2 are used as substrate HMG1 alone is degraded to give specific degradation products. We have also shown that the enzyme co-isolates with whole histone prepared by acid extraction of calf thymus nuclei, but interestingly it is not present in whole histone samples prepared in the same manner from pig thymus. A second chromatin bound protease which specifically cleaves histone H3 when whole histone is used as substrate has also been identified during the course of this work.