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Biomedical subjects

R Mathies

Publications and source records attributed to R Mathies.

At least 19 recordsLinked to original sources
PubMed1993

Dermatoglyphics in type 1 diabetes mellitus.

Although fingerprints and handprints are widely used in criminology, it is only recently that this approach has been applied to the field of medical and genetic diagnoses. In order to investigate dermatoglyphics in Type 1 diabetes mellitus, quantitative characteristics of fingers and palms (ridge count and main line indices) as well as qualitative parameters such as digital and interdigital patterns, the position of the palmar axial triradii and main line courses were analysed in 88 male and 108 female Type 1 diabetic patients and compared with data from 100 male and 99 female normal controls. Type 1 diabetic patients show a lower third finger ridge count (p < 0.05) and a-b ridge count (p < 0.001) and higher transversality of the main lines as indicated by the main line index value (p < 0.001) or the ending of the main line A in a specific sector 5, 5', and 5" (p < 0.001) compared with controls. In addition, diabetic patients show higher frequency of palmar axial t' and t" triradii (p < 0.001) and a lower frequency of 'true' patterns in the fourth interdigital and thenar area (p < 0.001) than controls. By multivariate analysis of quantitative and qualitative variables a predictive value of 78.6% and 77.3%, respectively, for male, and 81.4% and 82.2%, respectively, for female Type 1 diabetic patients was found. In conclusion, dermatoglyphics seem to be an interesting tool for genetic studies related to Type 1 diabetes.

Dermatoglyphics↗
PubMed1991

[Incidence and symptomatology of lung embolism in relation to the site of deep venous thrombosis].

The uncertainty about the true incidence of pulmonary embolism (PE) in connection with deep venous thrombosis (DVT) becomes evident when comparing the results of autopsy--vs. clinical studies, with the former showing a three-fold elevated rate of embolisation. In order to evaluate the percentage of clinically inapparent PE, all patients (65 females, 54 males, mean age 61.3 years) hospitalized between April 1989 and March 1990 with suspected DVT and/or PE underwent duplex-sonography and pulmonary scintigraphy. In 108 cases, DVT could be ascertained, whereas 11 patients only suffered from PE. In 57.4% of all DVT, PE was diagnosed. Of the 73 cases with PE, only 53.4% of the patient stated typical symptoms primarily. In more than 1/4 of the patients with primary symptoms of PE, no DVT could be diagnosed. There was no significant difference between the occurrence of PE in relation to the localisation of DVT, with 1/3 to 1/2 being asymptomatic. 1/4 of the patients with leg-thrombosis and 1/7 with thrombosis of the iliac vein did not complain of typical symptoms of thrombosis. Furthermore, an increased PE-rate seems to occur with an elevated ultrasound echogenity of the thrombus. As a result of the study pulmonary szintigrams seem to be indicated in all cases of DVT in order to evaluate the total PE risk.

Adult↗
PubMed1986

Investigations concerning the standardisation of control-investigations of supply-air in air-conditioning systems in hospitals.

In the following investigation, air-germ measurements were conducted--using the Reuter-Centrifugal-Sampler (RCS) and the Sartorius-Sampler MD 3 (SAR), and using standardized nutrient-substratum and breeding conditions--in order to detect differences in the measuring process itself. The aim of the study was to find a standard for routine-measurements in hospitals. A special "Supply-Air-Box" was developed because of the known turbulences during the emission of air from the channel; in order to cut off the interference-factor during the measurements caused by the blending with the room-air. The results of the air-germ measurements showed a sufficient reproducability and a good representation of the results in differing measuring positions with both devices during repeated measurements. A marked difference between the two measuring-devices are the markedly higher CFU-numbers in the measurements using the RCS-device and the resulting higher variability of the single-values. The measurements using the supply-air-box show that--with the usual measuring position immediately in front of the supply-air grille screen or without grille screen at the channel end--a considerable part of room-air is also registered during the determination of the CFU-number because of the existing turbulences. Because of the markedly lower CFU-numbers with this procedure, new recommendations were suggested for the maximal mean CFU-number in the supply-air. Accordingly, not more than 5 CFU/m3 of air should be found with three-step-filtered supply-air in well-maintained installations for the inrestricted utilization of the rooms, and not more than a mean value of 30 CFU/m3 of air with two-step-filtered supply-air.

Air Conditioning↗
PubMed1984

Solid-state 13C NMR studies of retinal in bacteriorhodopsin.

Solid-state 13C magic-angle sample spinning (MASS) NMR has been used to study lyophilized dark-adapted purple membrane containing 13C-labeled retinals. C-10-, C-11-, and C-12-labeled derivatives each showed two lines, assigned to the coexisting 13-cis and all-trans isomers. The isotropic chemical shifts, particularly of C-11, indicate that the Schiff base is protonated. Shift anisotropies are also similar to those of model compounds, indicating that this part of the chromophore is rigid and immobile and possesses the same degree of in-plane bending as crystalline retinal derivatives. Purple membrane samples labeled on the C-19- and C-20-methyl groups both give single lines from the retinal, upfield shifted by 2.1 and 1.0 ppm, respectively, from model compounds. In all cases, high-quality spectra were obtained from approximately 50-mg samples in modest signal-averaging times. These results suggest that it is now practical to exploit the enormous potential of MASS NMR for structural studies of 13C-labeled membrane proteins.

Bacteriorhodopsins↗
PubMed1984

Dark-adapted bacteriorhodopsin contains 13-cis, 15-syn and all-trans, 15-anti retinal Schiff bases.

13C NMR spectra of lyophilized dark-adapted [14-13C]retinyl-labeled bacteriorhodopsin show a large anomalous upfield shift for the 13C-14 resonance assigned to the 13-cis isomer, relative to both the all-trans isomer and model compounds. We attribute this to the so-called gamma effect, which results from a steric interaction between the C-14 retinal proton and the protons on the epsilon CH2 of the lysine. As a consequence of this observation, we infer that dark-adapted bacteriorhodopsin is composed of a mixture of all-trans, 15-anti (trans or E) and 13-cis, 15-syn (cis or Z) isomers. These occur in an approximate 4:6 ratio and are commonly identified as bR568 and bR548. This conclusion is based on an examination of the isotropic and anisotropic chemical shifts and a comparison with 13C shifts of the carbons adjacent to the C = N linkage in protonated ketimines. Other possible origins for the anomalous shift are examined and shown to be insufficient to account for either the size of the shift or the nature of the shift tensor. We discuss the consequences of this finding for the structure and photochemistry of bacteriorhodopsin.

Bacteriorhodopsins↗
PubMed1984

Determination of retinal Schiff base configuration in bacteriorhodopsin.

Resonance Raman spectra of the BR(568), BR(548), K(625), and L(550) intermediates of the bacteriorhodopsin photocycle have been obtained in (1)H(2)O and (2)H(2)O by using native purple membrane as well as purple membrane regenerated with 14,15-(13)C(2) and 12,14-(2)H(2) isotopic derivatives of retinal. These derivatives were selected to determine the contribution of the C(14)-C(15) stretch to the normal modes in the 1100- to 1400-cm(-1) fingerprint region and to characterize the coupling of the C(14)-C(15) stretch with the NH rock. Normal mode calculations demonstrate that when the retinal Schiff base is in the C[unk]N cis configuration the C(14)-C(15) stretch and the NH rock are strongly coupled, resulting in a large ( approximately 50-cm(-1)) upshift of the C(14)-C(15) stretch upon deuteration of the Schiff base nitrogen. In the C[unk]N trans geometry these vibrations are weakly coupled and only a slight (<5-cm(-1)) upshift of the C(14)-C(15) stretch is predicted upon N-deuteration. In BR(568), the insensitivity of the 1201-cm(-1) C(14)-C(15) stretch to N-deuteration demonstrates that its retinal C[unk]N configuration is trans. The C(14)-C(15) stretch in BR(548), however, shifts up from 1167 cm(-1) in (1)H(2)O to 1208 cm(-1) in (2)H(2)O, indicating that BR(548) contains a C[unk]N cis chromophore. Thus, the conversion of BR(568) to BR(548) (dark adaptation) involves isomerization about the C[unk]N bond in addition to isomerization about the C(13)[unk]C(14) bond. The insensitivity of the native, [14,15-(13)C(2)]-, and [12,14-(2)H(2)]K(625) and L(550) spectra to N-deuteration argues that these intermediates have a C[unk]N trans configuration. Thus, the primary photochemical step in bacteriorhodopsin (BR(568) --> K(625)) involves isomerization about the C(13)[unk]C(14) bond alone. The significance of these results for the mechanism of proton-pumping by bacteriorhodopsin is discussed.

Journal Article↗
PubMed1982

Resonance Raman spectra of bacteriorhodopsin's primary photoproduct: evidence for a distorted 13-cis retinal chromophore.

We have obtained the resonance Raman spectrum of bacteriorhodopsin's primary photoproduct K with a novel low-temperature spinning sample technique. Purple membrane at 77 K is illuminated with spatially separated actinic (pump) and probe laser beams. The 514-nm pump beam produces a photostationary steady-state mixture of bacteriorhodopsin and K. This mixture is then rotated through the red (676 nm) probe beam, which selectively enhances the Raman scattering from K. The essential advantage of our successive pump-and-probe technique is that it prevents the fluorescence excited by the pump beam from masking the red probe Raman scattering. K exhibits strong Raman lines at 1516, 1294, 1194, 1012, 957, and 811 cm-1. The effects of C15 deuteration on K's fingerprint lines correlate well with those seen in 13-cis model compounds, indicating that K has a 13-cis chromophore. However, the presence of unusually strong "low-wavenumber" lines at 811 and 957 cm-1, attributable to hydrogen out-of-plane wags, indicates that the protein holds the chromophore in a distorted conformation after trans leads to cis isomerization.

Bacteriorhodopsins↗
PubMed1982

Resonance Raman microscopy of rod and cone photoreceptors.

We have constructed a Raman microscope that has enabled us to obtain resonance Raman vibrational spectra from single photoreceptor cells. The laser beam which excites the Raman scattering is focused on the outer segment of the photoreceptor through the epiillumination system of a light microscope. Raman scattering from the visual pigment in the photoreceptor is collected by the objective and then dispersed onto a multichannel detector. High-quality spectra are recorded easily from individual outer segments that are 5 x 50 micrometer in size, and we have obtained spectra from cells as small as 1 x 10 micrometer. We have used the Raman microscope to study photostationary steady-state mixtures in pigments from toad (Bufo marinus) and goldfish (Carassius auratus) photoreceptors; these photoreceptors were frozen in glycerol glasses at 77 degrees K. Comparison of our toad red rod spectra with previously published spectra of bovine rod pigments demonstrates that the conformation of the chromophore in the first photointermediate, bathorhodopsin, is sensitive to variations in protein structure. We have also studied the first photointermediate in the goldfish rod photostationary steady-state. This bathoporphyropsin has a much lower ethylenic stretching frequency (1,507 cm-1) than that observed in the toad and bovine bathoproducts (approximately 1,535 cm-1). Preliminary results of our work on goldfish cone pigments are also reported. These are the first vibrational studies on the vertebrate photoreceptors responsible for color vision.

Animals↗
PubMed1980

Resonance Raman evidence for an all-trans to 13-cis isomerization in the proton-pumping cycle of bacteriorhodopsin.

Using a dual-beam flow technique, we have obtained resonance Raman spectra of the M412 photointermediates of both native purple membrane (15H M412) and purple membrane regenerated with 15-deuterioretinal (15D M412). For comparison, we have also obtained Raman spectra of the n-butylamine Schiff bases of the 13-cis and all-trans isomers of 15H and 15D retinal. The 15D model compound spectra, when compared to the 15H spectra, show isotopically induced spectral changes that are markedly different for the two isomers. There is a very close agreement between the frequency and intensity changes which occur upon deuteration of M412 and those which occur upon deuteration of the 13-cis model compound, but not even a qualitative correspondence exists when M412 and the all-trans model compound are similarly compared. These data demonstrate that the chromophore of M412 is an unprotonated Schiff base of 13-cis-retinal rather than all-trans-retinal. An analogous spectral comparison of 15H and 15D light-adapted bacteriorhodopsin (bRLA) with the 15H and 15D protonated Schiff bases of 13-cis- and all-trans-retinal demonstrates that bRLA contains an all-trans chromophore, in agreement with previous extraction experiments. Thus, a trans leads to cis isomerization occurs in the proton-pumping photocycle of Halobacterium halobium.

Bacteriorhodopsins↗
PubMed1980

Interpretation of the resonance Raman spectrum of bathorhodopsin based on visual pigment analogues.

Resonance Raman spectra of visual pigment analogues have been used to evaluate various models for the structure of the retinal chromophore in bathorhodopsin. Deuteration or removal of the 18-methyl on the beta-ionyl ring or of the 19-methyl on the polyene chain demonstrates that the three intense low wavenumber bands of bathorhodopsin at 853, 875, and 920 cm-1 are not due to exomethylene or ring modes. Rather, assignment of these lines to out-of-plane vinyl hydrogen motions on the chain best accounts for the experimental data. Our calculations show that the intensity of these vibrations can be explained by twists of 10-30 degrees about chain single bonds. The 1100-1400-cm-1 Raman fingerprint indicates that the configuration of the double bonds is trans. This suggests that the structure of the bathorhodopsin chromophore is twisted all-trans.

Animals↗
PubMed1979

Resonance Raman studies of bathorhodopsin: evidence for a protonated Schiff base linkage.

A dual beam pump/probe technique has been used with a 585-nm probe wavelength to obtain maximal resonance enhancement of the Raman lines of bathorhodopsin in a photostationary steady-state mixture at -160 degrees C. These studies show that bathorhodopsin has a protonated Schiff base vibration at 1657 cm(-1) which shifts upon deuteration to 1625 cm(-1). Within our experimental error (+/-2 cm(-1)) these frequencies are identical to those observed in rhodopsin and isorhodopsin. These effects show that the strength of the C=N bond and the degree of protonation of the Schiff base nitrogen are the same in bathorhodopsin, rhodopsin, and isorhodopsin. The implication of these results for the structure of the retinal chromophore in bathorhodopsin are discussed. The resonance Raman spectrum of pure bathorhodopsin has been generated by accurately subtracting the residual contributions of rhodopsin and isorhodopsin from spectra of the low temperature photostationary mixture. Bathorhodopsin is found to have lines at 853, 875, 920, 1006, 1166, 1210, 1278, 1323, 1536, and 1657 cm(-1). Also, by using an intensified vidicon detector, we have observed Raman scattering from bathorhodopsin at room temperature by generating a photostationary steady state with pulsed laser excitation. At room temperature the three characteristic lines of bathorhodopsin are found at 858, 873, and 920 cm(-1). The fact that the frequencies of these bathorhodopsin lines are nearly identical at both temperatures implies that the retinal conformation in bathorhodopsin formed at -160 degrees C is the same as that formed at room temperature.

Animals↗
PubMed1976

Rapid-flow resonance Raman spectroscopy of photolabile molecules: rhodopsin and isorhodopsin.

We have devised a method for obtaining the resonance Raman spectrum of a photolabile molecule before it is modified by light. The essence of this technique is that the sample is flowed through the light beam at a sufficiently high velocity so that the fraction of photoisomerized (or photodestroyed) molecules in the illuminated volume is very low. This rapid-flow technique has enabled us to measure the resonance Raman spectrum of unphotolyzed bovine rhodopsin in Ammonyx LO detergent solution and in sonicated retinal disc membranes. The major features of these spectra, which are very similar to one another, are the protonated Schiff base line near 1660 cm-1, the ethylenic line at 1545 cm-1, lines due to skeletal modes at 1216, 1240, and 1270 cm-1, and a line due to C-H bending at 971 cm-1. The resonance Raman spectrum of unphotolyzed isorhodopsin formed by the addition of 9-cis-retinal to opsin was also measured. The spectrum of isorhodopsin is more complex and differs markedly from that of rhodopsin. In isorhodopsin, the ethylenic line is shifted to 1550 cm-1, and there are six lines between 1153 and 1318 cm-1. The rapid-flow technique described here makes it feasible to control the extent of interaction between light and any photolabile molecule. We present a theory for predicting the effective sample composition in the illuminated volume as a function of the flow rate, light intensity, and spectral characteristics of the photolabile species.

Animals↗