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Biomedical subjects

P Engel

Publications and source records attributed to P Engel.

At least 91 records · Page 5Linked to original sources
PubMed1988

Purification and characterization of an endonuclease (E.C. 3.1.30.1) from Streptomyces tendae.

A single-strand-specific endonuclease which converted negatively supercoiled DNA to open-circular and linear DNA was purified to homogeneity with Hb-Sepharose 4B, DEAE Trisacryl M, HA-Ultrogel and PBE-94 chromatofocusing from extracts of Streptomyces tendae ATCC 31160. Bio-Gel P-200 chromatography and electrophoresis in SDS-PAGE indicated the native protein was a monomer with a molecular weight of approximately 40-kDa. This enzyme did not hydrolyze double-stranded linear DNA but digested RNA and circular single-strand DNA. Sequence specificity for nicking of negatively supercoiled DNA was not detected.

Chemical Fractionation↗
PubMed1988

Unfavourable outcomes of drug therapy--subjective probability versus confidence intervals.

To investigate how individual predictions compare with confidence intervals, we asked 50 medical residents and 28 graduate students with biostatistics training to estimate unfavourable outcomes of drug therapy (therapeutic failures and side-effects) in groups of 10 and 20 patients. The predictions made by physicians and graduate students were similar for both sample sizes and types of outcome. The majority (58%) of estimates were greater than the upper limit of the 95% confidence interval, a bias that may hamper the correct interpretation of therapeutic risks in medical decision-making.

Adult↗
PubMed1988

Rectal and rectal vs. esophageal temperatures in paraplegic men during prolonged exercise.

This study investigated the rectal (Tre), esophageal (Tes), and skin (Tsk) temperature changes in a group of trained traumatic paraplegic men pushing their own wheelchairs on a motor-driven treadmill for a prolonged period in a neutral environment. There were two experiments. The first experiment (Tre and Tsk) involved a homogeneous group (T10-T12/L3) of highly trained paraplegic men [maximum O2 uptake (VO2max) 47.5 +/- 1.8 ml.kg-1.min-1] exercising for 80 min at 60-65% VO2max.Tre and Tsk (head, arm, thigh, and calf) and heart rate (HR) were recorded throughout. O2 uptake (VO2), minute ventilation (VE), CO2 production (VCO2), and heart rate (HR) were recorded at four intervals. During experiment 1 significant changes in HR and insignificant changes in VCO2, VE, and VO2 occurred throughout prolonged exercise. Tre increased significantly from 37.1 +/- 0.1 degrees C (rest) to 37.8 +/- 0.1 degrees C after 80 min of exercise. There were only significant changes in arm Tsk. Experiment 2 involved a nonhomogeneous group (T5-T10/T11) of active paraplegics (VO2max 39.9 +/- 4.3 ml.kg-1.min-1) exercising at 60-65% VO2max for up to 45 min on the treadmill while Tre and Tes were simultaneously recorded. Tes rose significantly faster than Tre during exercise (dT/dt 20 min: Tes 0.050 +/- 0.003 degrees C/min and Tre 0.019 +/- 0.005 degrees C/min), and Tes declined significantly faster than Tre at the end of exercise. Tes was significantly higher than Tre at the end of exercise. Our results suggest that during wheelchair propulsion by paraplegics, Tes may be a better estimate of core temperature than Tre.

Body Temperature↗
PubMed1987

Plasmid transformation of Streptomyces tendae after heat attenuation of restriction.

Streptomyces tendae ATCC 31160 produces nikkomycin, a fungicide and insecticide that inhibits chitin synthases. Exposure of S. tendae protoplasts to 50 degrees C for 30 min is required for transformation (10(2) thiostrepton-resistant transformants micrograms of DNA-1) with plasmid pIJ702 or pIJ680 from Streptomyces lividans. pIJ702 and pIJ680 DNA isolated from the S. tendae transformants is efficient (10(6) to 10(7) transformants micrograms of DNA-1) in subsequent transformations of S. tendae protoplasts generated at 30 degrees C. PstI fails to cut the single PstI site in pIJ702 and cuts only one of the two PstI sites in pIJ680 DNA isolated from S. tendae transformants. Digests of plasmid DNA mixtures showed that plasmid DNA from S. tendae does not inhibit PstI activity. pIJ702 and pIJ680 DNA from S. tendae transformants was used to transform S. lividans to show that plasmid DNA remains unchanged, except for modification at some PstI sites in S. tendae, as a consequence of passage through S. tendae. The DNA modification is lost when S. lividans is transformed with plasmid DNA from S. tendae transformants. Since S. tendae modifies only some PstI sites, it appears the modification (presumably restriction activity also) activity in S. tendae recognizes a sequence that includes or overlaps the PstI hexanucleotide recognition sequence.

Aminoglycosides↗
PubMed1986

Technological and physiological characteristics of a newly developed hand-lever drive system for wheelchairs.

It may be concluded that, by use of the newly developed Swing-Turn-gear system, mobility of the disabled person using wheelchairs outdoors can be improved. The qualities of the drive gear in push and pull action, the free wheel, the full selection of frequency, and the range of moving the hand levers represent important progress in wheelchair engineering research. The handrim drive is an alternative, especially for indoor use. But, for the first time, an indoor wheelchair can be offered as a combination vehicle for both indoor and outdoor use. The acceptance of the new wheelchair integrated Swing-Turn-gear is much better than the conspicuous hand-lever drive in standard outdoor wheelchairs. At present, the German wheelchair manufacturer, MEYRA Vlotho, is preparing the new hand-lever drive system for production. Initially, the drive system will be adapted to a standard indoor wheelchair made by this company. Development of a lever drive system is also in progress in the United States, which employs force transmission characteristics in one direction.

Energy Metabolism↗
PubMed1984

Immune complexes in retinitis pigmentosa.

In a group of 46 patients with retinitis pigmentosa (RP) we studied the presence of circulating immune complexes (CIC) and the alterations in the complement system. Our results showed the presence of CIC in 43.5% of the patients studied, reduced levels of the complement components C3 and C4 (p less than 0.001), and of the haemolytic activity CH50 (p less than 0.001) when compared with a control group consisting of a 100 healthy subjects. We found a statistically significant correlation between the values of C3 and CIC (p less than 0.01), C4 and CIC (p less than 0.01), and between CH50 and CIC (p less than 0.001). These findings indicate that the CIC may play a role in the pathogenesis of primary retinitis pigmentosa.

Adolescent↗
PubMed1984

Immune complexes in retinitis pigmentosa.

In a group of 46 patients with retinitis pigmentosa (RP), we studied the levels of IgM, the presence of a rheumatoid factor (RF), the circulating immune complexes (CIC) and the alterations in the complement system. Our results showed increased IgM levels in two patients (226 and 260 mg/dl), the presence of RF in three patients (205, 187 and 80 IU/ml), the existence of CIC in 43.5% of the subjects, reduced levels of the complement components C3 and C4 (p less than 0.001) and of the haemolytic activity CH50 (p less than 0.001) when compared with a control group consisting of 100 healthy subjects. We found a statistically significant correlation between the values of C3 and CIC (p less than 0.01), C4 and CIC (p less than 0.01) and between CH50 and CIC (p less than 0.001).

Antigen-Antibody Complex↗
PubMed1984

Cytostatic and cytotoxic response of Ehrlich ascites tumor cells in vivo on chronic treatment with cytarabine, bleomycin, and peplomycin.

The cytokinetic response of Ehrlich ascites tumor (EAT) cells in vivo upon chronic treatment at low dosage levels with cytarabine (1-beta-D-arabinofuranosylcytosine, ara-c) bleomycin (BLM) and peplomycin (PEP) was estimated. Bivariate DNA histograms allow the simultaneous evaluation of the cell cycle status of living and killed cells. It could be confirmed that ara-C is cytostatic on cells in S phase. Pronounced cytotoxicity was observed in G1 and G2+M phase. BLM and PEP showed no (or neglectable ) accumulation of vital cells in any cycle phase. Both drugs, however, are cytotoxic on cells, regardless their position within the cell cycle. A successive application of ara-C and BLM (or PEP) in a cell kinetics-directed therapy schedule may be taken into account.

Animals↗
PubMed1984

T cell subsets in allergic respiratory disease using monoclonal antibodies.

Fifty patients with perennial allergic rhinitis and extrinsic allergic asthma were studied to determine the relative percentages of OKT3+, OKT4+ and OKT8+ cells as well as the OKT4+/OKT8+ ratios. The percentages of the OKT3+ cells (66 +/- 7) were reduced when compared with those of 50 healthy controls (72 +/- 6), (p less than 0.001). The mean values and deviations of the OKT4 marker produced no statistically significant differences between the patient group (44 +/- 6) and the control group (44 +/- 6). A reduction in the OKT8+ marker in the patient group was registered (20 +/- 6), (p less than 0.001). The OKT4+/OKT8+ ratio was, as a result, raised in the patient group (2.3 +/- 0.6) in relation to the control group (1.6 +/- 0.3). The reduction in the OKT3+ cells together with the imbalance in the subset inducer-helper/cytotoxic-suppressor in allergic respiratory disease could lead to non-regulation of B cells and to hyperproduction of IgE.

Adolescent↗
PubMed1984

Cell mediated immunity in perennial allergic rhinitis.

The authors studied a group of 72 patients with perennial allergic rhinitis. The following parameters were determined: the distribution of T total and T active and B lymphoid populations, non-specific T suppressor activity induced by concanavalin-A, response indices to stimulation by phytohaemagglutinin and pokeweed mitogen and levels of serum IgE. Comparison with 100 healthy controls showed a diminution with respect to the T total lymphoid subpopulation (p less than 0.001) and the suppressor activity (p less than 0.001). There was no significant change regarding the T active and B values and the lymphoproliferative response to the phytohaemagglutinin and pokeweed mitogen. A correlation was seen between the IgE levels (elevated in 62.5% of patients) with the T suppressor activity which was statistically significant (p less than 0.01).

Adolescent↗
PubMed1983

Differentiation of constrictive pericarditis and restrictive cardiomyopathy using digitized echocardiography.

Constrictive pericarditis and restrictive cardiomyopathy are difficult to distinguish at the bedside and occasionally at routine cardiac catheterization. Left ventricular diastolic function was studied by computer analysis of digitized M-mode echocardiograms in four patients with constrictive disease and three with restrictive disease, and the data were compared with those of normal subjects. The respective distinguishing echographic features of constrictive pericarditis and restrictive cardiomyopathy were as follows: the major filling period of the left ventricle was 78 +/- 9% of normal versus 128 +/- 4% (p less than 0.01), minimal left ventricular dimension to peak filling interval was 50 +/- 10 versus 110 ms (p less than 0.05) and the maximal rate of left ventricular posterior wall thinning was -4.9 versus -2.3 seconds-1 (p less than 0.05). This preliminary study suggests that it may be possible to accurately diagnose the two disease entities using this technique at the bedside and to avoid cardiac catheterization.

Adolescent↗
PubMed1983

Thermoregulatory set point in patients with spinal cord injuries (spinal man).

The thermoregulatory set point in man can be estimated by the aid of quantifying thermal alliesthesial responses. Behavioural and autonomous thermoregulation in a group of nine patients with spinal cord transection was compared against a control group of six non-disabled under various room-climate conditions. Deviation of core temperature from thermoregulatory set point was estimated using a behavioural indicator (thermal alliesthesial responses) at different intervals of the exposure time. General thermal comfort sensation was rated on a subjective thermal comfort scale. The group with spinal cord transections showed, as expected, a state of partial poikilothermia. Mean skin temperature was approximately the same in both groups, but skin temperature distribution was different in the spinal cord transection when compared against the control group. The results of thermal alliesthesial responses indicated that core temperature for those with spinal cord transections were closer to their thermoregulatory set points than in the control group. It has been concluded that under conditions beyond thermal neutrality the spinal man may possess, some time after the injury, a thermoregulatory set point which varies directly with ambient thermal conditions. This phenomenon is viewed as an adaptive thermoregulatory process following spinal cord injury.

Adaptation, Physiological↗
PubMed1981

The treatment of decubitus ulcers with dextranomer.

Twenty-five patients with 35 bedsores were treated with dextranomer (Debrisan; Adcock Ingram) applied topically to the ulcers. Fourteen patients had ulcers which penetrated fascia, muscle and bone, 4 had superficial ulcers and 2 had discharging sinuses. Most of the severe ulcers healed rapidly and were cleansed and ready for surgery at an average of 14.6 days. The superficial ulcers were completely healed within 3 weeks. Treatment of the sinuses with dextranomer using a catheter/syringe technique resulted in wound closure within 28 days. In a representative sample of 12 patients in whom the surface area of the ulcers was measured by means of a planimeter, there was a median reduction in surface area of 44.8% by the 2nd week (P=0,0002) and 79% (P=0,001) at the end of the 4th week. The median percentage reduction in depth was 66.7% (P=0,008) at the end of the 4th week.

Administration, Topical↗