Showing papers by "University of Milan published in 1987"

Relationship of 24-hour blood pressure mean and variability to severity of target-organ damage in hypertension.

Abstract: Casual blood pressure (BP) can predict the development of cardiovascular morbidity and mortality, but the correlations between its values and the subsequent occurrence of such complications are low. This may depend on different individual resistance to the damage produced by hypertension. However, it may also depend on the recognized inability of causal BP to reflect accurately the 24-h mean and profile BP. In order to test the latter hypothesis, 24-h BP was recorded intra-arterially (Oxford method) in 108 hospitalized subjects with essential hypertension ranging from mild to severe. The 24-h means and standard deviations (i.e. variabilities) for systolic, mean and diastolic BP obtained by computer analysis of the BP tracing were related to the rate and severity of target-organ damage (TOD) assessed by clinical examination and quantified according to a predetermined score. The results confirmed that 24-h BP may be variably different from cuff BP among subjects. For nearly any value of cuff BP, subjects in whom the 24-h mean BP was low had a lower prevalence and severity of TOD than those in whom the 24-h mean BP was high (P less than 0.01). Furthermore, for nearly any level of 24-h mean BP, subjects in whom the 24-h BP variability was low had a lower prevalence and severity of TOD than those in whom the 24-h BP variability was high (P less than 0.05). These findings demonstrate that the severity of hypertension is more closely related to 24-h mean BP than to cuff BP values.(ABSTRACT TRUNCATED AT 250 WORDS)

Pressure-volume curve of total respiratory system in acute respiratory failure. Computed tomographic scan study.

Abstract: To investigate the relationship between lung anatomy and pulmonary mechanics in acute respiratory failure (ARF), 20 patients with ARF underwent computerized tomography (CT) at 3 levels of positive end-expiratory pressure (PEEP) (5, 10, and 15 cm H2O). The static pressure-volume curve of the total respiratory system and the lung volumes (helium dilution method) were also measured. By knowing the lung volumes and analyzing the CT number frequency distribution, a quantitative estimate of normally aerated, poorly aerated, and nonaerated lung tissue was obtained at each level of PEEP. The recruitment was defined as the percent increase of normally aerated tissue from 5 to 15 cm H2O. We found that the different compliances (starting compliance, inflation compliance, and deflation compliance) were correlated only with the amount of normally aerated tissue present in the range of pressures explored by a given compliance (5 cm H2O for starting compliance and 15 cm H2O for inflation and deflation compliances). No relationship was found between the compliances and the poorly aerated and nonaerated tissue. The specific compliance was in the normal range, whereas the amount of recruitment was related to the ratio of inflation compliance to starting compliance. Our data suggest that (1) the pressure-volume curve parameters in ARF investigate only the residual healthy zones of the lung and do not directly estimate the "amount" of disease (poorly or nonaerated tissue), (2) the pressure-volume curve may allow an estimate of the anatomic recruitment, and (3) the residual normally aerated zones of the ARF lung seem to maintain a normal intrinsic elasticity.

Verbal and spatial immediate memory span: normative data from 1355 adults and 1112 children.

Abstract: Norms are provided for verbal and visuo-spatial immediate memory span, two tasks widely used in the clinical assessment of short-term memory and its neurological disorders. Data have been collected from 1355 male and female adult subjects, with various educational backgrounds and a 20–99 years age range. Span shows a major decrement after the late sixties and is affected by educational level. Male subjects score better on the spatial task. Data collected from 1112 male and female children, 4-to-10 year-old, show that span increases with age and boys score better on the spatial test.

Altered Gs and adenylate cyclase activity in human GH-secreting pituitary adenomas.

Abstract: Gs and Gi are guanine nucleotide-binding, heterotrimer proteins that regulate the activity of adenylate cyclase, and are responsible for transferring stimulatory and inhibitory hormonal signals, respectively, from cell surface receptors to the enzyme catalytic unit. These proteins can be directly activated by agents such as GTP and analogues, fluoride and magnesium. Decreased amounts of Gs and Gi, and even the absence of Gs, have been described, whereas an altered Gs has been reported in a cultured cell line (UNC variant of S49 lymphoma cells), but has never been observed in human disease states. We have found a profoundly altered Gs protein in a group of human growth hormone-secreting pituitary adenomas, characterized by high secretory activity and intracellular cyclic AMP levels. In the membranes from these tumours no stimulation of adenylate cyclase activity by growth hormone-releasing hormone, by GTP or by fluoride was observed. Indeed, the last two agents caused an inhibition, probably mediated by Gi. In contrast, adenylate cyclase stimulation by Mg2+ was enormously increased. This altered pattern of adenylate cyclase regulation was reproduced when a cholate extract of the tumour membranes (which contains G proteins) was reconstituted with Gs-free, cyc- S49 cell membranes. Inasmuch as secretion from somatotrophic cells is known to be a cAMP-dependent function, the alteration of Gs could be the direct cause of the high secretory activity of the tumours in which it occurs.

Alerting reaction and rise in blood pressure during measurement by physician and nurse.

Abstract: Blood pressure was monitored by a continuous intra-arterial recording in 46 subjects to investigate whether the alarm reaction and the blood pressure and heart rate increases that occur during cuff blood pressure measurement made by a physician 1) attenuate when the physician's visit is repeated several times and 2) are less pronounced if a nurse measures the blood pressure. In 16 subjects the peak mean blood pressure and heart rate rises that occurred in the early part of the physician's first visit (22.6 +/- 1.8 mm Hg and 17.7 +/- 1.7 beats/min) were virtually identical to those occurring during three subsequent visits by the same physician throughout a 2-day intra-arterial blood pressure monitoring. The less pronounced pressor and tachycardic responses observed in the last part of the physician's visit also were virtually identical among the four visits. In contrast, in 30 other subjects the blood pressure and heart rate rises that occurred during the nurse's visit were 46.7% and 42.1% less (p less than 0.01) than those occurring during the physician's visit. The late and less pronounced pressor and tachycardic responses to the visit were also significantly less (p less than 0.01) in the former than in the latter condition. These results indicate that the error of overestimation of blood pressure inherent in cuff blood pressure measurement by a physician cannot be avoided by repeated visits by the physician over a short time span. It clearly can be reduced, however, if blood pressure measurements are performed by a nurse.

Raven's coloured progressive matrices: normative values on 305 adult normal controls.

Abstract: The use of Raven's Coloured Progressive Matrices (PM 47) in experiments with brain-damaged patients is briefly reviewed. Because norms for adults are still not available, normative data were calculated on 305 normals; corrections for age and education and centile allocation of the scores are furnished.

Fura-2 measurement of cytosolic free Ca2+ in monolayers and suspensions of various types of animal cells.

Abstract: The fluorescent indicator fura-2 has been applied to a variety of cell types in order to set up appropriate conditions for measurements of the cytosolic concentration of free ionized Ca2+ [( Ca2+]i) in both cell suspensions and single cells analyzed in a conventional fluorimeter or in a fluorescence microscope equipped for quantitative analyses (with or without computerized image analyses), respectively. When the usual procedure for fluorescence dye loading (i.e., incubation at 37 degrees C with fura-2 acetoxy-methyl ester) was used, cells often exhibited a nonhomogeneous distribution of the dye, with marked concentration in multiple small spots located preferentially in the perinuclear area. These spots (studied in detail in human skin fibroblasts), were much more frequent in attached than in suspended cells, and were due to the accumulation (most probably by endocytosis) of the dye within acidic organelles after hydrolysis by lysosomal enzyme(s). When loading with fura-2 was performed at low (15 degrees C) temperature, no spots appeared, and cells remained diffusely labeled even after subsequent incubation at 32-37 degrees C for up to 2 h. Homogeneous distribution of the dye is a prerequisite for appropriate [Ca2+]i measurement. In fact, comparison of the results obtained in human skin fibroblasts labeled at either 37 or 15 degrees C demonstrated in spotty cells a marked apparent blunting of Ca2+ transients evoked by application of bradykinin. Additional problems were encountered when using fura-2. Leakage of the dye from loaded cells to the extracellular medium markedly affected the measurements in cell suspensions. This phenomenon was found to depend on the cell type, and to markedly decrease when temperature was lowered, suggesting the involvement of a facilitated transport. Calibration of fluorescence signals in terms of absolute [Ca2+]i was complicated by the increased fluorescence of fura-2 in the intracellular environment. To solve this problem we propose an in situ calibration procedure based on measurements carried out on cells in which [Ca2+]i was massively lowered (by loading the probe in a Ca2+-free medium) or increased (by treatment with the Ca2+ ionophore ionomycin, applied in a medium containing 3 mM Ca2+). These results provide explanations and, at least partial, solutions to the major problems encountered when using fura-2, and should thus be of help in clarifying the proper usage of the dye in [Ca2+]i measurements.

Brain pathology induced by infection with the human immunodeficiency virus (HIV). A histological, immunocytochemical, and electron microscopical study of 100 autopsy cases.

Abstract: Neuropathological examination of brain tissue of 100 patients with infection by the human immunodeficiency virus (HIV), including 98 with clinically manifest acquired immune deficiency syndrome (AIDS), revealed distinct multifocal-disseminated and diffuse brain tissue lesions, which can be regarded as HIV-induced brain lessions: multifocal giant cell encephalitis (MGCE; 4) and progressive diffuse leukoencephalopathy (PDL; 25). These lesions were found in 38 brains, and in 17 in absence of infectious, necrotizing or inflammatory changes of other types. In 13 brains, a combination of MGCE with PDL was seen, suggesting a spectrum of HIV-induced brain lesions. MGCE is characterized by perivascular accumulations predominantly of rod cells, monohistiocytes and macrophages, all of which are strongly labeled with a monoclonal antibody to macrophages. Most conspicuous are multinucleated giant cells which are also labeled by anti-macrophage antibody, and which can be regarded as evidence of the local presence of HIV, as confirmed by electron microscopical detection of HIV particles in four MGCE brains, and by immunocytochemical detection of HIV proteins in two MGCE brains. PDL is characterized by a triad: diffuse myelin loss, astroglial proliferation, and infiltration by mono- and multinucleated macrophages. HIV-induced lesions can be morphologically differentiated from histopathological brain lesions known in immunosuppression, including what is called here nodular encephalitis [“subacute encephalitis” of the literature, in most cases attributable to cytomegalovirus (CMV) or toxoplasmosis], by their characteristic histopathology including the hallmark presence of multinucleated giant cells, by direct immunocytochemical and electron microscopical demonstration of HIV in the lesions, and by the absence of opportunistic agents (bacteria, fungi, Toxoplasma, CMV, HSV or papovaviruses). Diffuse poliodystrophy (diffuse proliferation of astroglia with swollen nuclei, occasionally minor neuronal loss and rod cell proliferation) was found in the cerebral cortex and other gray matter in half of all brains, including cases with gyral atrophy, and may be another correlate of HIV damage to the brain. Morphological delineation of HIV-induced brain lesions is a necessary prerequisite for a meaningful clinical definition of HIV-induced cerebral disease.

Excitability of the soleus H-reflex arc during walking and stepping in man

Abstract: In eight normal subjects, the excitability of the soleus (Sol) H-reflex was tested in parallel with Sol length changes, EMGs of leg and thigh muscles and ground contact phases, during three different pacing movements: bipedal treadmill walking, single limb treadmill walking, and single-limb stepping on one spot. A computerized procedure was used which compensated for changes in stimulus effectiveness that occurred during free motion. In the three paradigms examined, significant excitability modulations were observed with respect to a control level determined in standing weight-bearing position. During bipedal treadmill walking, excitability was decreased in the early stance, maximally enhanced in the second half of the stance, and again decreased during the end-stance and the whole swing phase, with a minimum value around the toe off period. The main modulation pattern was retained during single-limb treadmill walking. During single-limb stepping on one spot, the stance-phase increase in excitability and the swing phase depression were still present. However, in the second half of the swing phase, reflex responsiveness returned to reference level, which was maintained during the subsequent contact period. Moreover, a decrease in reflex excitability was detected around the mid-stance. The time course of the described modulations was only partly correlated with the EMG and length changes of the Sol muscle. Furthermore, in the three movements tested, during the early stance phase, the excitability of the H-reflex arc did not correspond to the one expected on the basis of the available H-reflex studies performed under static conditions. It is suggested that, at least in certain stride phases (e.g. around the early contact period), an active regulation affects the transmission in the Sol myotatic arc during the pacing movements investigated.

Systematic ab initio configuration-interaction study of alkali-metal clusters: Relation between electronic structure and geometry of small Li clusters.

Abstract: The electronic and geometric structure of small neutral ${\mathrm{Li}}_{\mathrm{n}}$ (n=2--9) and cationic ${\mathrm{Li}}_{\mathrm{n}}$${\mathrm{}}^{+}$ (n=2--9) clusters is investigated with the optimal self-consistent-field energy and geometry search and with the multireference diexcited configuration-interaction method. The optimal geometries of neutral and cationic Li clusters are very different. Very small ${\mathrm{Li}}_{\mathrm{n}}$ (n\ensuremath{\le}6) clusters prefer planar geometries [deformed sections of the (111) fcc-lattice plane]. The optimal geometries of somewhat larger ${\mathrm{Li}}_{\mathrm{n}}$ (6\ensuremath{\le}n\ensuremath{\le}9) clusters are composed from condensed deformed tetrahedra. This switch in the geometrical structure of clusters can be easily understood on the basis of some simple qualitative arguments. Predicted relatively large stabilities of ${\mathrm{Li}}_{4}$ and ${\mathrm{Li}}_{8}$ as well as of ${\mathrm{Li}}_{3}$${\mathrm{}}^{+}$ and ${\mathrm{Li}}_{9}$${\mathrm{}}^{+}$ can help to interpret the ``magic numbers'' observed when alkali-metal clusters are prepared and detected under differing experimental conditions. The theory predicts stability of relatively small doubly charged alkali-metal clusters which seems to be in variance with the customary ideas of ``Coulomb explosion.'' The general trend of the dependence of ionization potentials of alkali-metal clusters on the cluster nuclearity agrees with experiments. The present work confirms some conclusions of the ``electron-shell model'' but puts them on a more general basis, independent of conceptual and methodological details. Furthermore, it reveals new aspects and leads to predictions.

Activation of a muscarinic receptor selectively inhibits a rapidly inactivated Ca2+ current in rat sympathetic neurons

Abstract: Sympathetic neurons dissociated from the superior cervical ganglion of 2-day-old rats were studied by whole-cell patch clamp and by fura-2 measurements of the cytosolic free Ca2+ concentration, [Ca2+]i. Step depolarizations in the presence of tetrodotoxin and hexamethonium triggered two Ca2+ currents that differed in the voltage dependence of activation and kinetics of inactivation. These currents resemble the L and N currents previously described in chicken sensory neurons [Nowycky, M. C., Fox, A. P. & Tsien, R. W. (1985) Nature (London) 316, 440-442]. Treatment with acetylcholine resulted in the rapid (within seconds), selective, and reversible inhibition of the rapidly inactivated, N-type current, whereas the long-lasting L-type current remained unaffected. The high sensitivity to blocker drugs (atropine, pirenzepine) indicated that this effect of acetylcholine was due to a muscarinic M1 receptor. Intracellular perfusion with nonhydrolyzable guanine nucleotide analogs or pretreatment of the neurons with pertussis toxin had profound effects on the Ca2+ current modulation. Guanosine 5'-[gamma-thio]triphosphate caused the disappearance of the N-type current (an effect akin to that of acetylcholine, but irreversible), whereas guanosine 5'-[beta-thio]diphosphate and pertussis toxin pretreatment prevented the acetylcholine-induced inhibition. In contrast, cAMP, applied intracellularly together with 3-isobutyl-1-methylxanthine, as well as activators and inhibitors of protein kinase C, were without effect. Acetylcholine caused shortening of action potentials in neurons treated with tetraethylammonium to partially block K+ channels. Moreover, when applied to neurons loaded with the fluorescent indicator fura-2, acetylcholine failed to appreciably modify [Ca2+]i at rest but caused a partial blunting of the initial [Ca2+]i peak induced by depolarization with high K+. This effect was blocked by muscarinic antagonists and pertussis toxin and was unaffected by protein kinase activators. Thus, muscarinic modulation of the N-type Ca2+ channels appears to be mediated by a pertussis toxin-sensitive guanine nucleotide-binding protein and independent of both cAMP-dependent protein kinase and protein kinase C.

Benefits and risks of protracted treatment with human recombinant erythropoietin in patients having haemodialysis.

Abstract: Fourteen patients with uraemic anaemia and having regular haemodialysis were given human recombinant erythropoietin in increasing doses, beginning with 24 U/kg thrice weekly. One patient was dropped from the study because of recurrent thrombosis of vascular access sites. In the other 13 patients, followed up for a mean of 9.1 months (range 8-11), haemoglobin concentrations increased from 62 (SD 8) to 105 (9) g/l. No antierythropoietin antibodies were detected during the study. The correction of anaemia was associated with a tendency to hyperkalaemia and a mild increase of unconjugated bilirubinaemia. In eight previously hypertensive patients antihypertensive treatment had to be reinforced, but in normotensive patients blood pressure did not change. Thrombosis of arteriovenous fistulas occurred in two patients and a cerebral ischaemic lesion in one. Protracted treatment with human recombinant erythropoietin evidently can maintain normal haemoglobin concentrations in uraemic patients over time. Full correction of anaemia, however, may trigger some vascular problems, particularly in hypertensive patients and those with a tendency to thromboembolism.

Heart rate variability signal processing: a quantitative approach as an aid to diagnosis in cardiovascular pathologies

Abstract: The heart rate variability (HRV) signal carries important information about the systems controlling heat rate and blood pressure, mainly elicited by autonomic nervous system (sympathetic and parasympathetic) controls. The present paper illustrates methods of HRV signal processing by using autoregressive (AR) modeling and power spectral density estimate. The information enhanced in this way seems to be particularly sensitive in discriminating various cardiovascular pathologies (hypertension, myocardial infarction, diabetic neuropathy, etc.). This method provides a simple non-invasive analysis, based on the processing of spontaneous oscillations in heart rate. Particular emphasis is directed to the algorithms used and to their direct application by using proper computerized techniques: only a few paradigmatical examples will be illustrated as preliminary results.

Reflex excitability of human soleus motoneurones during voluntary shortening or lengthening contractions.

Abstract: 1. We investigated the possibility that increase or decrease in the monosynaptic reflex excitability of the soleus muscle in man might play a role in matching the muscle mechanical output to the voluntary command aimed at performing isotonic contractions or relaxations, at various velocities. 2. Rectified and integrated electromyographic activity (e.m.g.) and the H reflex of soleus were measured during plantar flexions against a constant load (shortening contractions) or dorsal flexions resisting the load (lengthening contraction), performed without activation of pretibial muscles. 3. At the same ankle joint angle, integrated e.m.g. was larger during shortening contractions than during lengthening contractions. During shortening contractions, integrated e.m.g. increased as a function of the velocity of plantar flexion. During lengthening contractions, integrated e.m.g. decreased as a function of dorsal flexion and angular velocity and nearly disappeared in the last part of the most rapid lengthening contractions. 4. During shortening contractions, the H reflex increased beyond the extent expected for the level of e.m.g. activity; during lengthening contractions, reduction of the H reflex below control values at rest occurred in spite of background e.m.g. activity. 5. When the level of e.m.g. activity was kept constant, the above changes in H reflex were larger in both directions as a function of the velocity of the movement. 6. Passive rotation in the dorsal direction contributed to the inhibition observed during lengthening contractions. 7. It is suggested that these changes in the excitability of the H reflex, probably presynaptic in origin, serve the purpose of appropriately modulating the rate and extent of motoneurone recruitment during shortening and lengthening contractions. This allows the foot to follow a constant-velocity path in spite of the perturbing effects of the spindle afferent inputs and of the muscle characteristics described by the force--length and force--velocity diagrams.

Electrochemical surface properties of Co3O4 electrodes

Abstract: The electrochemical behaviour of Co3O4 layers deposited by thermal decomposition of Co(NO3)2 at 200–500°C on titanium supports with and without an interlayer of RuO2 has been studied by cyclic voltammetry, chronopotentiometry and potential step experiments in alkaline solutions. Such variables as the calcination temperature, the solution pH, the potential sweep rate and the oxide loading have been investigated in detail to determine their influence on voltammetric peaks and voltammetric charge. Insight has been gained into the relevance of the latter to surface area determination and to proton diffusion into the oxide layer. The role of the support-active layer interface and especially that of the RuO2 interlayer has been scrutinized. The importance of surface studies for the understanding of the electrocatalytic behaviour of Co3O4 electrodes has been analysed.

Soybean protein diet increases low density lipoprotein receptor activity in mononuclear cells from hypercholesterolemic patients.

Abstract: The effect of two diets containing different protein sources (animal vs. soybean) on the low density lipoprotein (LDL) receptor activity was tested in freshly isolated mononuclear cells from 12 individuals with severe type II hyperlipoproteinemia. The two diets, both taken for 4 wk in a crossover design were of otherwise identical composition. During the soybean protein diet period, total cholesterol was reduced by 15.9% and LDL-cholesterol by 16.4%. The diet containing animal proteins exerted no significant change in plasma lipid levels vs. the baseline findings. The soybean diet regimen dramatically affected the degradation of LDL by mononuclear cells. Degradation was increased 16-fold vs. the basal activity and 8-fold compared with the standard low lipid diet with animal proteins. There was, however, no clear relationship between the reduction of total and LDL-cholesterolemia and the increased LDL degradation. These findings confirm similar data previously obtained in cholesterol-fed rats and suggest that some factor/s, most likely of a protein nature, may regulate the expression of lipoprotein receptors in peripheral cells, particularly when receptor activity is suppressed by experimental diets and/or spontaneous hypercholesterolemia.

Interaction between photosystem I and ferredoxin. Identification by chemical cross-linking of the polypeptide which binds ferredoxin.

Abstract: Ferredoxin has been effectively cross-linked to photosystem I complex by treatment of purified particles or thylakoids with N-ethyl-3-(3-dimethylaminopropyl)carbodiimide, a zero-length cross-linker which stabilizes protein-protein electrostatic interactions. Analysis of photosystem I polypeptide composition after such a treatment showed a specific decrease of the 20-kDa subunit and the appearance of a new component of about 42 kDa which was recognized by the anti-ferredoxin antibody. Cross-linking of ferredoxin to thylakoids allowed the membrane preparation to photoreduce cytochrome c without requiring exogenous ferredoxin, whereas photosystem I particles purified from treated thylakoids were inactivated in the NADP+ photoreduction activity. From these results, it can be inferred that the polypeptide of 20 kDa is the photosystem I subunit which interacts with ferredoxin during the photosynthetic electron transport.

The monitoring of optimal experience. A tool for psychiatric rehabilitation.

Abstract: This article illustrates the use of quantitative time-sampling data in developing a psychology of “optimal experience” to help in the psychiatric development of adequate rehabilitation approaches. The Experience-Sampling Method was used on a sample of 47 Italian adolescent students to measure fluctu

Protective effect of vagal stimulation on reperfusion arrhythmias in cats.

Abstract: The role of the autonomic nervous system in modulating reperfusion arrhythmias is still unclear. Experiments with sympathetic denervation or alpha- and beta-adrenergic blocking agents have provided mixed results, while the effect of parasympathetic activation has not been investigated extensively. The effect of bilateral vagotomy and of vagal stimulation was studied, with and without attendant bradycardia, on the incidence of reperfusion arrhythmias in alpha-chloralose anesthetized cats. The left anterior descending coronary artery was occluded for 20 minutes, followed by reperfusion in 105 animals. The incidence and severity of reperfusion arrhythmias was compared in 1) neurally intact animals (heart rate 208 +/- 24 beats/min), 2) animals with acute bilateral vagotomy (heart rate 233 +/- 25 beats/min), 3) animals with vagal stimulation adjusted to maintain heart rate at 90-100 beats/min, and 4) animals with vagal stimulation + ventricular pacing to maintain heart rate at prestimulation values. All the neurally intact and vagotomized animals developed complex reperfusion arrhythmias, but these arrhythmias occurred in only 60 and 72%, respectively, of the animals with vagal stimulation and vagal stimulation + pacing (p less than 0.005 vs. neurally intact and p less than 0.02 vs. vagotomy). The incidence of ventricular fibrillation was similar in neurally intact (62%) and vagotomized (58%) animals; it was strikingly lower (7%, p less than 0.01) in animals with vagal stimulation when heart rate was allowed to decrease, and it was 48% when heart rate was kept constant during vagal stimulation. A selective protection from sustained (greater than 30 seconds duration) ventricular tachycardia was observed in animals with vagal stimulation independent of heart rate changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation of a Pseudomonas stutzeri strain that degrades o-xylene.

Abstract: A Pseudomonas stutzeri strain capable of growing on o-xylene was isolated from enrichment cultures. The organism grew on 2,3- and 3,4-dimethylphenol but not on 2-methylbenzyl alcohol, o-tolualdehyde, or o-toluate. P. stutzeri was not able to utilize m-xylene, p-xylene, or 1,2,4-trimethylbenzene, but growth was observed in the presence of the corresponding alcohols and acids. From the Pseudomonas cultures supplied with o-xylene, 2,3-dimethylphenol was isolated and identified. When resting P. stutzeri cells were incubated with 2,3-dimethylphenol, the reaction mixture turned greenish yellow and showed spectral properties identical to those of the 3,4-dimethylcatechol meta ring fission product. Catechol 2,3-oxygenase was induced by growth on o-xylene or on 2,3- or 3,4-dimethylphenol. The suggested hypothesis is that the first metabolic steps of growth on o-xylene involve the direct oxygenation of the aromatic nucleus, followed by meta pathway reactions.

Peripheral neuropathy in macroglobulinemia: incidence and antigen-specificity of M proteins.

Abstract: Peripheral neuropathy was found in 12 (46%) of 26 patients with macroglobulinemia. The neuropathy was subclinical in two. Anti-myelin-associated glycoprotein (MAG) activity was found in six (50%) patients with neuropathy. Sural nerve biopsies showed demyelination and IgM deposits on the myelin sheath. In one patient who had no anti-MAG activity, the serum IgM bound to peripheral myelin by indirect immunofluorescence and to several protein bands in peripheral nerve and other tissues by immunoblot. In the other five patients with neuropathy, we found no binding of M proteins to nerve components, but in three patients there were endoneurial IgM deposits in nerve biopsy. Peripheral neuropathy may be related to the antigen-specificity of M proteins.

A possible new tool for clinical diagnosis of melanoma: The computer

Abstract: The analysis of cutaneous melanoma images by two coupled computers (IBM 7350/4361) was carried out on twenty color slides. Each color slide was digitized with a spatial reduction of 25 x 25 Rm. Classic technics of digital image analysis and new algorithms were used to (1) improve the contrast on the full image or a portion of it, (2) contrast a skin lesion with statistical information deduced from another lesion, (3) evaluate the shape of the lesion, the roughness of the surface, and the transition region from the lesion to the normal skin, and (4) analyze a lesion from the chromatic point of view. The theoretical reasons of interest are (1) to have an objective method that is easy to standardize and reliably repeatable and (2) to be able to analyze details not perceivable by the human eye. If the same technic are used in the evaluation of histologic characteristics of the lesions, a chance of making much more sophisticated clinicopathologic correlations will be available. The system needs to be improved at the technical level so that the response time of acquisition of the digitized images is shortened by the use of a digital television camera and the development of new computer programs to be run on a small computer. Evaluation of the system's sensitivity and specificity and an adequate clinical trial are needed.