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Biomedical subjects

W Sperling

Publications and source records attributed to W Sperling.

35 records · Page 2Linked to original sources
PubMed1983

Bathorhodopsin intermediates from 11-cis-rhodopsin and 9-cis-rhodopsin.

Bathorhodopsin-rhodopsin difference spectra of native 11-cis-rhodopsin and regenerated 9-cis-rhodopsin were measured at room temperature with a double-beam laser spectrophotometer after excitation at 532 nm. A detailed analysis of data obtained at 85 psec after excitation suggests that the bathorhodopsins generated from 11-cis- and 9-cis-rhodopsin differ in their extinction coefficients and that their absorption maxima are shifted in wavelength by about 10 nm from one another. The ratio of quantum yields for photochemical production of the 11-cis-bathorhodopsin and the 9-cis-bathorhodopsin approximates 1. Implications that the early photochemical processes in vision are more complex than previously considered are explored.

Animals↗
PubMed1980

Photosensory retinal pigments in Halobacterium halobium.

In Halobacterium halobium, nicotine is known to block the synthesis of retinal. Cells grown in the presence of nicotine do not show any photophobic response. Addition of retinal1 or retinal2 restored the photophobic responses to light-increase in the UV and to light-decrease in the green-yellow part of the spectrum. The action spectra of the two retinal2-photosystems were red-shifted by 15--20 nm, compared with the corresponding retinal1 systems. We conclude that each of the two photosystems PS 370 and PS 565, has its own photosensory pigment with retinal as the chromophoric group.

Animals↗
PubMed1980

Efficacy of troleandomycin in outpatients with severe, corticosteroid-dependent asthma.

Sixteen severe, corticosteroid-dependent yet resistant outpatient asthmatics were treated with troleandomycin (TAO), a macrolide antibiotic, in an attempt to both induce a clinical remission and reduce methylprednisolone requirements. Within the first 2 wk of initiating TAO therapy, 50% of the patients experienced a greater than 20% increase in forced expiratory volume in 1 sec (FEV1) and 80% noted a greater than 20% increase in forced vital capacity between 25% and 75% (FVC 25%-75%). Maximal increases in FEV1 and FVC 25%-75% were noted in all patients within the first 6 wk on TAO and methylprednisolone. There was a concomitant clinical improvement in all patients. Corticosteroid-induced side effects, gastrointestinal tract discomfort, and elevated serum glutamic pyruvic transaminase (SGPT) were common yet generally transient during TAO and methylprednisolone therapy. After a 4- to 18-mo follow-up 15/16 patients were well-controlled on TAO and methylprednisolone. Methylprednisolone requirements were reduced at least four- to fivefold in most patients during TAO therapy. Normal morning serum cortisol levels were documented after varying intervals in most patients when both TAO (250 mg) and methylprednisolone (4 to 16 mg) could be reduced to alternate-day administration. Only one patient was forced to discontinue therapy due to side effects. The present study extends the effectiveness of TAO therapy to ambulatory asthmatics, establishes a clinical strategy that maximizes benefit/risk factors, and provides practical guidelines for the long-term use of TAO and methylprednisolone.

Adolescent↗
PubMed1975

The resolution of arterial pulses into forward and backward waves as an approach to the determination of the characteristic impedance.

Pressure and flow recordings from a given site in an artery can be used for the resolution of the pulse wave into its forward and backward components if the characteristic impedance (Z) is known. The principle of this method was reported by von Kries in 1892. In the present work, the procedure is first applied to a theoretical, non-uniform tube model. The characteristic impedance of the model are assumed to be real magnitudes. From the results it is seen that the calculated backward wave provides a criterion which indicates whether the true value of Z actually has been used for the resolving procedure. If, as in the case of natural pulses, Z is not known, its value can be obtained by repeatedly performing the resolving procedure using various values of Z, and choosing the value of Z employed to calculate the backward wave which best fits the criterion. The method is demonstrated on pulses of the abdominal aorta and carotid artery of the dog. The results are compared with the average values of the input impedance in the higher frequency range.

Analog-Digital Conversion↗
PubMedDate not supplied

Leptin is associated with craving in females with alcoholism.

The appetite and weight regulating peptide leptin was associated recently with alcohol craving during withdrawal. Nevertheless, correlations were only significant with craving displayed on the visual analogue scale for maximum craving during the previous week (VAS), and not if assessed with the highly validated Obsessive Compulsive Drinking Scale (OCDS). The objective of the following study, therefore, is to elucidate further the associations between the leptin system and craving concepts during alcohol withdrawal. A sufficiently large sample size should allow multiple statistical subgroup and confounder analyses. We prospectively investigated 102 chronic alcoholic inpatients (23 females, 79 males) during withdrawal on days 0 (admission), 1, 2 and days 7-10. In addition to the statistical analysis of the total sample, females and males were to be analysed separately. For detecting associations between leptin levels and craving scores multiple regression analysis was performed. Plasma leptin levels were determined, and craving for ethanol was assessed by both the OCDS and the VAS. Leptin plasma levels significantly increased during alcohol withdrawal compared to day 0, while all craving scores decreased. Body mass corrected leptin plasma levels predicted craving on day 0 in the OCDS total score (R=0.55, F=7.91, df=1.19, p<0.05) and in the OCDS obsessive subscore (R=0.57, F>=8.48, df=1.19, p<0.05) in females. Neither in males nor in the total population did multiple regression analysis reveal any significant results. Leptin levels seem to change during inpatient alcohol withdrawal. In a multivariate model, correlations between leptin levels and the highly validated craving scores of the OCDS can only be assumed in females. Hence, gender differences have to be taken into account when searching for neurobiological models of alcohol craving.

Adult↗
PubMedDate not supplied

The concept of abnormal hemispheric organization in addiction research.

In addition to the established areas of endogenous psychoses, the concept of abnormal hemispheric organization in the field of psychiatry is also generating ever greater interest in the area of research into addiction. On the basis of the demonstrably higher rate of developmental risk factors (pre-, peri-, postnatal), in particular the marker left-handedness (LH) has been interpreted as an indication of induced hemispheric 'malcontrol' in endogenous psychoses. In various studies, elevated rates of LH have also been shown in alcoholics. Alcoholism could be related to biological factors associated with anomalous cerebral dominance. In a joint study carried out by the Anton Proksch Institut in Vienna (Austria), and the University of Erlangen-Nuremberg (Germany) involving a total of 250 alcohol-dependent inpatients, the hypothesis of deviant laterality in the presence of an elevated frequency of developmental risk factors has been confirmed exclusively in male alcoholics. A comparison of subtypes has also revealed that Type IV in the Lesch typology, and Type II in the Cloninger classification, are more vulnerable subtypes. These results clearly show that there are differences to be found within the overall group of alcoholics, and underscore the need for subtyping and gender-specific studies.

Alcoholism↗
PubMedDate not supplied

Moderate alcohol consumption in social drinkers raises plasma homocysteine levels: a contradiction to the 'French Paradox'?

Evidence from observational studies suggests that elevated levels of homocysteine are associated with an increased risk of cardiovascular diseases. We assessed whether moderate alcohol intake in healthy social drinkers, suggested to be cardioprotective according to the 'French paradox', influences the cardiovascular risk factor homocysteine. A total of 60 normal nourished subjects who had no evidence of vascular disease or other risk factors for hyperhomocysteinaemia were assigned to receive mineral water or 30 g of alcohol per day (as beer, red wine or spirits) for a period of 6 weeks. Homocysteine levels of social drinkers, independent of which beverage was consumed, increased during the observation. We postulate that elevated levels of homocysteine in social drinkers with regular moderate alcohol intake are at risk of developing cardiovascular diseases, which contradicts the suggested cardioprotection of alcohol according to the 'French paradox'.

Adult↗
PubMedDate not supplied

Lack of association between hippocampal volume reduction and first-onset alcohol withdrawal seizure. A volumetric MRI study.

AIMS AND METHODS: Magnetic resonance imaging (MRI) of the hippocampus has been extensively studied in both neurological and psychiatric disorders. Furthermore, hippocampal volume reductions on MRI have been reported in patients with chronic alcoholism. The present volumetric MRI study was undertaken to determine whether an association exists between hippocampal volume reduction and first-onset alcohol withdrawal seizure. Until recently, no data as to whether hippocampal volume reductions in alcoholics might serve as a predictor of withdrawal seizures were available. RESULTS: We found the average hippocampal volumes measured by high resolution MRI to be significantly reduced in 52 alcoholics compared with 30 healthy controls. Besides a decrease of hippocampal volume in patients with chronic alcoholism, we could not find any significant correlation between the occurrence of seizures during alcohol withdrawal and the amount of hippocampal volume reduction in these patients. CONCLUSIONS: Thus, the alcoholism-related atrophy within the hippocampal formation in patients suffering from chronic alcoholism does not seem to be the source of convulsive activity in these patients. Neither does the amount of atrophy allow the occurrence of first-onset withdrawal seizures to be predicted.

Adult↗
PubMedDate not supplied

Non-right-handedness and obstetrical complications in paranoid hallucinatory schizophrenics.

In previous studies a link between pregnancy complications, minor physical anomalies and non-right-handedness was described in schizophrenic patients. There is evidence of an anomaly in the lateralization process in schizophrenia. Many studies of handedness and schizophrenia have found that schizophrenic patients have an increased rate of non-right-handedness compared with normal subjects. The contemporary neurodevelopmental hypothesis of schizophrenia emerged from pathobiological findings. In addition there is evidence for early brain lesions and malformations in fetal brain development. Especially pregnancy and birth complications have been found to be a risk factor for the later development of schizophrenia. In this study we set out to test the possible association between diagnosis and handedness, diagnosis and risk factors, as well as gender and handedness for 60 patients (30 men, 30 women) and 60 controls. The percentage of non-right-handedness was significantly elevated in the patient group (p = 0.0025). In a gender-specific analysis this result could be confirmed only for male patients. Peri- and postnatal developmental risk factors were significantly elevated in schizophrenics compared with controls. The percentage of all risk factors in the male group of schizophrenic non-right-handers was significantly elevated compared with right-handed male schizophrenics.

Adult↗