Differential responsiveness of simple and complex cells in cat striate cortex to visual texture

Summary The responsiveness of 254 simple and complex striate cortical cells to various forms of static and dynamic textured visual stimuli was studied in cats, lightly anaesthetised with N₂O/O₂ mixtures supplemented with pentobarbitone.Simple cells were unresponsive to all forms of visual noise presented alone, although about 70% showed a change in responsiveness to conventional bar stimuli when these were presented on moving, rather than stationary, static-noise backgrounds. Bar responses were depressed by background texture motion in a majority of cells (54%), but were actually enhanced in a few instances (16%).In contrast, all complex cells were to some extent responsive to bars of static visual noise moving over stationary backgrounds of similar texture, or to motion of a whole field of static noise. The optimal velocity for noise was generally lower than for bar stimuli.Since moving noise backgrounds were excitatory for complex cells, they tended to reduce specific responses to bar stimulation; in addition, directional bias could be modified by direction and velocity of background motion.Complex cells fell into two overlapping groups as regards their relative sensitivity to light or dark bars and visual noise. Extreme examples were insensitive to conventional bar or edge stimuli while responding briskly to moving noise.In many complex cells, the preferred directions for motion of noise and of an optimally oriented black/white bar were dissimilar.The ocular dominance and the degree of binocular facilitation of some complex cells differed for bar stimuli and visual texture.Preliminary evidence suggests that the deep-layer complex cells (those tolerant of misalignment of line elements; Hammond and MacKay, 1976) were most sensitive to visual noise. Superficial-layer complex cells (those preferring alignment) were less responsive to noise.Only complex-type hypercomplex cells showed any response to visual noise.We conclude that, since simple cells are unresponsive to noise, they cannot provide the sole input to complex cells. The differences in the response of some complex cells to rectilinear and textured stimuli throw a new light on their rôle in cortical information-processing. In particular, it tells against the hypothesis that they act as a second stage in the abstraction of edge-orientation.     

Structural-mechanical properties and swelling of protein complexes of hyaluronate and protein-chrondroitin-4-sulfate

Structural-mechanical strength and swelling of gels consisting of gelatin and potassium hyaluronate (PHY) or potassium protine-chondroitin-4-sulfate (PPCS) were shown to depend on the ratio between the components. With low concentrations of PHY and PPCS the minimum of structural-mechanical strength coincided with the maximum of swelling of the gels. In zones of neutralization of the positive electric charges of gelatin by macropolyanions, high structural-mechanical strength of the gels coincided with the minimum of swelling. In high concentrations of PHY, structural-mechanical strength and swelling of the gel became equal to the values characteristic of a gel consisting of gelatin only, but in high concentration of PPCS there was an additional parallel increase in this strength and in swelling of the gel.(Presented by Academician of the Academy of Medical Sciences of the USSR S. S. Debov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 10, pp. 1211–1213, October, 1976.     

Stage, survival and delays in lung, colorectal, prostate and ovarian cancer: comparison between diagnostic routes

BACKGROUND: Very few studies have reported cancer outcomes of patients referred through different routes, despite the prominence of current UK cancer urgent referral guidance. AIM: This study aimed to compare outcomes of cancer patients referred through the urgent referral guidance with those who were not, with respect to stage at diagnosis, survival, and delays in diagnosis. Design of study: Analysis of hospital records. SETTING: One hospital trust in England. METHOD: The records of 889 patients diagnosed in 2000-2001 with one of four types of cancer were analysed: 409 with lung cancer; 239 with colorectal cancer; 146 with prostate cancer; and 95 with ovarian cancer. Outcome measures were diagnostic stage, survival, referral and secondary care delays. RESULTS: For lung cancer, urgent referrals had more advanced TNM (tumor, node, metastasis) stage than patients diagnosed through other routes (P = 0.035) and poorer survival (P = 0.020). There was no difference in stage or survival for the other cancers. For each cancer, a higher proportion of urgent referrals was seen within 2 weeks. Secondary care delays for lung and colorectal cancer were shorter for inter-specialty referrals. CONCLUSION: For patients with lung cancer, the guidance appears to be prioritising those in the more advanced stages of disease. This was not the case for the other three cancers. Referral delays were shorter for patients urgently referred, as is the intention of the guidance. The avoidance of delays in outpatient diagnostics probably accounts for shorter secondary care delays for inter-specialty referrals.     

Selective accumulation of monoclonal antibodies against neurospecific enolase in brain tissue of rats with middle cerebral artery occlusion

Preparations of I¹²⁵-labeled monoclonal antibodies against neurospecific enolase and mouse plasma IgG1 were injected intravenously to rats immediately after unilateral occlusion of the middle cerebral artery. Radioactivity of I¹²⁵-labeled monoclonal antibodies against neurospecific enolase in the brain tissue progressively increased, reached a maximum by the 48th hour, and remained practically unchanged after 72 h. At the same time radioactivity of labeled IgG1 in the brain tissue and radioactivity of both preparations in the blood, liver, spleen, kidneys, heart, and lungs decreased over 72 h. Selective accumulation of I¹²⁵-labeled monoclonal antibodies against neurospecific enolase was less significant in the brain tissue of the contralateral hemisphere and cerebellum not exposed to ischemia.Translated from Byulleten Eksperimentalnoi Biologii i Meditsiny, Vol. 138, No. 10, pp. 388–392, October, 2004     

Simultaneous detection of SCE and Q-bands on human chromosomes by a double-staining technique

Human lymphocytes were cultured for two cell cycles in the presence of bromodeoxyuridine (BrdU), and the resulting metaphase chromosomes were first stained with quinacrine mustard (QM) and then, immediately afterwards, with Hoechst 33258, without any intermediate destaining. Both Q-banding patterns and sister chromatid differential staining were photographed subsequently on the same metaphase using two different filter blocks of the fluorescence microscope.     

Body temperature is elevated in the early postmortem period

During the collection of specimens at autopsy for biochemical analysis, it was observed that body temperatures were higher than expected. To evaluate this observation further, rectal temperatures were determined at the earliest feasible time after death in 20 adult patients for whom recent premortem rectal temperatures were available for comparison. The average premortem temperature was 37.6 degrees C (range, 34.9 to 41.1 degrees C) and had been obtained 19 to 240 minutes (average, 107 minutes) before death. The average postmortem temperature, also 37.6 degrees C (range, 35.5 to 41.3 degrees C), was obtained 116 to 401 minutes (average, 202 minutes) after death. In the 11 patients in whom the postmortem interval was less than three hours (average, 155 minutes), there was an average postmortem temperature increase of 0.5 degree C (range, +1.3 to -0.7 degree C). The results suggest that there is usually an initial postmortem elevation in body temperature as measured rectally, probably as a result of continuing tissue and bacterial metabolism in the absence of the usual heat-dispersal mechanisms. This phenomenon should be considered when postmortem materials are used for analysis or when postmortem interval is determined by body temperature.     

Benzbromarone disposition and uricosuric action; evidence for hydroxilation instead of debromination to benzarone

Summary Benzbromarone is one of the main uricosuric drugs currently used. We determined plasma concentrations of benzbromarone, bromobenzarone, and benzarone and 24 hour uric acid excretion in ten healthy individuals following fasting application of two different non-micronised benzbromarone brands. In addition we explored the influence of adjusting urinary pH to near neutral values and of concomitant food intake. Benzbromarone was more rapidly absorbed from the test preparation than from the reference preparation; the extent of systemic availability did not differ significantly. Urinary pH adjustment had no clearcut effect, whereas food intake retarded drug absorption (even though not significant because of the variability of the data). Binding of benzbromarone to plasma proteins exceeded 99%. Bromobenzarone and benzarone were not detectable and are unlikely to be major metabolites of benzbromarone. Instead we found two other compounds suggestive of metabolites, one of them being monohydroxilated benzbromarone. The plasma concentrations of the parent compound in one subject exceeded those of the rest of the group, possibly indicating genetic differences in drug metabolism. The uricosuric effect was not related to benzbromarone plasma concentrations.Abbreviations AUC area under the (plasma concentration time) curve - GC-MS gas chromatography-mass spectrometry - HPLC high performance liquid chromatography - t1/2 plasma elimination half life Dedicated to Professor Dr. N. Zöllner on the occasion of his 65th anniversary     

Learning and retention of a shock avoidance task by rat using deafferented hind limb

Learning and retention of a shock avoidance task were studied in the absence of proprioceptive or other topographic feedback. Rats with a deafferented hind limb were trained using the instrumental shock avoidance and retention paradigm of Horridge. Rats received shock whenever they lowered an electrode attached to a deafferented hind foot into an electrolyte bath; yoked-control rats received the shocks to a deafferented hind food along with the experimental animals. Experimental animals consistently held their feet above the electrolyte (p<0.01). During the early minutes of the second phase (a testing situation, in which the experimental and control animals were both shocked for leg lowering) the experimentals received fewer shocks than the controls (p<0.001); the controls eventually withheld their feet (p<0.001). These results indicate that rats with deafferented hind limbs provide a simple system for the study of learning and retention in the absence of proprioceptive or other topographic feedback.     

Angled aorta ("sigmoid septum") as a cause of hypertrophic subaortic stenosis

Review of the hearts of seven patients in whom hypertrophic obstructive cardiomyopathy had been diagnosed by the usual clinical and morphologic criteria revealed diminished angles between the interventricular septa and ascending aortas in three cases. The angles in these three hearts were 90 to 110 degrees, as compared with a mean value of 145 degrees in the other four hearts with hypertrophic obstructive cardiomyopathy and 140 +/- 14 degrees in 55 control hearts. None of the patients with hypertrophic subaortic stenoses and angled aortic roots died of the heart disease, and none had either asymmetric ventricular hypertrophy or evidence of familial cardiomyopathy. It is proposed that in patients with angled aortic roots and left ventricular hypertrophy, subaortic obstruction may develop due to narrowing of the left ventricular outflow tract, resulting in clinical and morphologic findings of hypertrophic obstructive cardiomyopathy. In hearts with angled aortic roots the top of the ventricular septum is tipped toward the mitral valve, rather than tapered toward the aorta, as in normal hearts. This configuration narrows the outflow tract of the left ventricle and can result in systolic anterior motion of the mitral valve, the illusion of asymmetric septal hypertrophy when studied by M-mode echocardiography, a subaortic pressure gradient, and a subaortic endocardial plaque. This less serious form of hypertrophic subaortic stenosis should be distinguished from other forms of hypertrophic obstructive cardiomyopathy.