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Biomedical subjects

M Haider

Publications and source records attributed to M Haider.

At least 37 records · Page 2Linked to original sources
PubMed1998

Gestational breast cancer.

OBJECTIVE: To study the problems of breast imaging in gestational breast cancer. PATIENTS AND METHOD: Retrospective review of the charts of 19 patients with breast cancer detected during pregnancy or lactation or within 1 year of delivery, who were referred to a tertiary centre for adjuvant therapy between 1986 and 1996. For 10 patients who underwent breast imaging, mammograms and breast ultrasonograms or reports were requested from outside facilities. RESULTS: The patients ranged in age from 23 to 41 years (mean 31 years). All 19 patients presented with palpable tumours; in 7 patients, the tumours were stage T2 or higher; in 11 patients, the tumours were at an advanced stage with positive axillary nodes. In 11 of the patients there was a delay in diagnosis, which ranged from 2 to 16 months. Of the 8 mammograms that could be reviewed, 5 showed infiltrating ductal carcinomas with typical features, which were detected as a mass (in 1 case), a mass with microcalcifications (in 1 case), microcalcifications (in 2 cases) and asymmetry (in 1 case). Three mammograms were negative, including 1 obtained from a patient with extensive comedocarcinoma. Breast ultrasonograms obtained from 4 patients (2 of whom also had mammograms) showed solid hypoechoic masses; in 2 of the ultrasonograms, the masses simulated a benign lesion. CONCLUSIONS: Although breast cancer during pregnancy and lactation is rare, this study suggests that radiologists should include it in the differential diagnosis of a solid breast mass seen during pregnancy or lactation. Clinicians appear to be reluctant to use breast imaging in these patients; however, this can lead to a delay in diagnosis. Ultrasonography is the modality of choice for initial analysis of such a mass in this age group. Mammography with shielding of the abdomen is recommended if there is suspicion of cancer. Clinical, mammographic and sonographic findings should be integrated for optimum interpretation.

Adult↗
PubMed1997

Identification and phenotypic analysis of two glyoxalase II encoding genes from Saccharomyces cerevisiae, GLO2 and GLO4, and intracellular localization of the corresponding proteins.

We have isolated and characterized two genes coding for the glyoxalase II enzyme from Saccharomyces cerevisiae. The coding region of the GLO2 gene corresponds to a protein with 274 amino acids and a molecular mass of 31,306 daltons. The open reading frame of the GLO4 gene could be translated into a protein with 285 amino acids and a molecular mass of 32,325 daltons. The amino acid sequences of the deduced proteins are 59.1% identical and show high similarities to the sequence of the human glyoxalase II. When grown on either glucose or glycerol as a carbon source, a glo2 glo4 double deletion strain contains no glyoxalase II activity at all and shows no obvious phenotype during vegetative growth. However, this strain showed a similar high sensitivity against exogenous methylglyoxal as compared with a glyoxalase I-deficient strain. Whereas the GLO2 gene is expressed on both glucose and glycerol, the GLO4 gene is only active on glycerol. The active Glo2p protein is localized in the cytoplasm and the active Glo4p in the mitochondrial matrix. Heterologous expression of the full-length GLO2 coding region in Escherichia coli resulted in an active protein. However, to get an active Glo4p protein in E. coli, the putative mitochondrial transit peptide at the N-terminal end had to be removed by shortening the 5' end of the GLO4 open reading frame.

Amino Acid Sequence↗
PubMed1994

Clastogenic effects of radiofrequency radiations on chromosomes of Tradescantia.

The clastogenicity of electromagnetic fields (EMF) has so far been studied only under laboratory conditions. We used the Tradescantia-micronucleus (Trad-MCN) bioassay in an in situ experiment to find out whether short-wave electromagnetic fields used for broadcasting (10-21 MHz) may show genotoxic effects. Plant cuttings bearing young flower buds were exposed (30 h) on both sides of a slewable curtain antenna (300/500 kW, 40-170 V/m) and 15 m (90 V/m) and 30 m (70 V/m) distant from a vertical cage antenna (100 kW) as well as at the neighbors living near the broadcasting station (200 m, 1-3 V/m). The exposure at both sides of the slewable curtain antenna was performed simultaneously within cages, one of the Faraday type shielding the field and one non-shielding mesh cage. Laboratory controls were maintained for comparison. Higher MCN frequencies than in laboratory controls were found for all exposure sites in the immediate vicinity of the antennae, where the exposure standards of the electric field strength of the International Radiation Protection Association (IRPA) were exceeded. The results at all exposure sites except one were statistically significant. Since the parallel exposure in a non-shielding and a shielding cage also revealed significant differences in MCN frequencies (the latter showing no significant differences from laboratory controls), the clastogenic effects are clearly attributable to the short-wave radiation from the antennae.

Chromosome Aberrations↗
PubMed1994

Different patterns of light exposure in relation to melatonin and cortisol rhythms and sleep of night workers.

There is strong evidence to suggest that circadian psychophysiological adaptation processes are modified by light, depending on its intensity and timing. To characterize such modifications and determine whether they are associated with an alteration in the day/night pattern of melatonin excretion, measurements were obtained around the clock in 14 permanent night workers, each studied over a 48 hr period in the field. The light exposure behavior of these workers was studied with a newly developed light dosimetry by measuring light intensity at eye level. Physical activity was continuously registered and sleep indices were obtained by sleep logs and activity markings. Circadian rhythms of melatonin and cortisol were analysed from salivary samples collected for 24 hr at 2 hr intervals. The interindividual variation of melatonin acrophase determined by cosinor analysis was greater than 180 degrees (from around midnight to noon) and that of cortisol was about 135 degrees (from early morning to afternoon). Hormonal phase positions coincided significantly with light exposure: the more bright light pulses in the morning (maximum lux between 0600 and 0900), the less were the melatonin and cortisol acrophases shifted into the day. There was also a negative correlation between melatonin acrophase shift and duration of the overall light exposure above 1500 lux. Morning light maximum and sleep onset correlated highly significantly. Night workers were divided into those with less than ('non-shifters', n = 9) and more than 6 hr deviation from midnight ('shifters', n = 5) of the melatonin acrophase. The group comparison revealed a marked difference of the mean melatonin concentrations at night, and at 0700.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Concentration evaluation of chromatin in unstained resin-embedded sections by means of low-dose ratio-contrast imaging in STEM.

Quantitative STEM with the imaging mode of ratio-contrast was investigated in order to evaluate the local concentration of DNA in situ for different kinds of DNA plasms in terms of intracellular packing densities (p.d.). The ability of ratio imaging to suppress thickness variations provided the basis to use unstained sections from cryofixed and freeze-substituted material. The DNA p.d. within the nucleoid of E. coli was determined to be about 100 mg ml-1. Quantitative data concerning the p.d. of DNA in condensed eukaryotic chromatin assuming equal amounts of DNA and protein were evaluated for the first time: approximately 400 mg ml-1 chromatin which corresponds to 200 mg ml-1 DNA. The p.d. of DNA in chromosomes from the dinoflagellate Amphidinium carterae, a eukaryote devoid of histones and with only small relative amounts of histone-like protein, was also found to be of the order of 200 mg ml-1. The highest p.d. of DNA was measured for the head of the bacteriophage T4 with more than 800 mg ml-1, in fair agreement with previous calculations. The results provide further support for a condensation mode of low protein chromatins that involves a liquid-crystalline organization of the DNA filaments.

Animals↗
PubMed1993

Personal light dosimetry in permanent night and day workers.

Light exposure was measured in six day and six night watches (working 12-hour shifts five days in a row) during 48 h on work days and 48 h on days off using a photocell with a sensitivity corresponding to photopic vision. The photocell was mounted on a frame of spectacles, thus measuring in viewing direction. Light exposure was low both in night and day watches; however, in night watches exposures were significantly lower: On work days, night watches spent a mean of 13 min above 1,500 lx, day watches 52 min; on days off, night watches spent 3 min above 1,500 lx but day watches 89 min. Unexpectedly, night watches had no higher exposure during days off. We suspect that this is due to a light avoidance tendency in permanent night workers. High negative correlations between the acrophases of subjective state (e.g., alertness and mood) and light exposure in night watches indicate that bright light would probably increase desynchronization between subjective state, sleep, and activity.

Adult↗
PubMed1993

[Connection between air quality and room climate and estimation of dwellings by health-impaired inhabitants].

The investigation was performed in winter 1990 and 1991 when measurements were taken in 16 dwellings of patients, recruited from a pulmologic outpatient centre. Patients suffered from repeated respiratory irritations which they attributed to dwelling conditions. Inhabitants reported by means of questionnaires and standardized scales the dwelling situation and their dwelling behaviour, subjective ratings of indoor environmental quality as well as ratings of wellbeing. The load of indoor pollutants (CO2, CO, NO2, HCHO), biological agents (fungal spores, house dust mites) as well as indoor climate factors were assessed. The measurements revealed an evident load at least in one parameter; in the majority of dwellings combined loads of air pollutants and biological agents were apparent. Homes supplied with gas as main energy source had significantly higher concentrations of CO2, CO and NO2. At noon, exposure limits of CO2 and NO2 were frequently exceeded. Inhabitants of homes being supplied with electricity instead of gas gave significantly better air quality ratings. The correlations between the average score concerning the rated health quality of their homes and the rate of excess of exposure limits are significant: The health quality ratings are significantly related to the concentrations of "air quality indicators", which induce the feeling of stale air (CO2) and mucosa irritations (NO2). Ratings of wellbeing are significantly connected to objective parameters, i.e. NO2 baseline load, fungal spores in the air and the difference between wall-air temperature. Our study suggests that people suspecting a connection between their health impairment and dwelling conditions should be taken serious. The measurement program proved to be a suitable screening procedure to assess adverse environmental influences in homes. More homes should be investigated to further support our findings.

Air Pollution, Indoor↗
PubMed1992

[The rectus abdominis syndrome].

Three athletes (one female, two males), aged 18-21 years, developed acute abdominal pain, two of them immediately after exercise including abdominal muscle training. The female patient had a pulmonary infection of uncertain cause at the time. The second patient obviously suffered from an allergic or parasitic disease (eosinophilia of 26%). The third patient, a swimmer, had the symptoms in the course of a flu-like infection after drinking about 100 g alcohol. Serum creatinine kinase activity was 7,800-17,500 U/l, making acute muscle damage likely, probably rhabdomyolysis. Ultrasound examination revealed echo-dense areas of the rectus abdominis muscle in two of the patients, in one of them associated with marked muscle swelling. In the third patient ultrasound was unremarkable during a symptom-free interval 8 days after the onset of symptoms. These observations indicate that even during banal infections sport exercise involving special strain on the abdominal musculature should not be undertaken because of the risk of rhabdomyolysis.

Abdominal Muscles↗
PubMed1991

[Effect of molsidomine on thrombocyte aggregation in unstable angina pectoris after parenteral administration of nitroglycerin].

In the present study, we took whole blood from 12 patients treated with heparin, acetylsalicylic acid, and nitroglycerin i.v., to measure the aggregability of platelets after acute and prolonged i.v. application of nitroglycerin and after oral application of molsidomine. Aggregation was induced by platelet-activating-factor (PAF). As a measure for platelet aggregability, we determined the PAF-concentration needed to induce irreversible aggregation (threshold dose) and the maximum slope of the aggregation curve with 50 nM PAF. At the beginning, 1 h after the onset of nitroglycerin infusion (3 mg/h), 24 h and 1 h after increasing the nitroglycerin dose (5 mg/h), neither the maximum slope nor the threshold dose for PAF-induced aggregation differed significantly. However, after additional oral application of molsidomine the maximum slope of the aggregation curve decreased significantly. These data indicate that molsidomine decreases the aggregability of platelets in patients, even after pretreatment with heparin, acetylsalicylic acid, and nitroglycerin.

Angina, Unstable↗
PubMed1991

[Current methods in blood preservation: recovery of blood components using a multi-bag system].

A new method of blood preparation by use of a multiple plastic bag system is prescribed. Buffy coat free red cell suspensions in additive solution (SAG-M), fresh frozen (recovered) plasma and random platelet concentrates can thus be produced. Apart from the so far clinically not instantaneously available stored platelets the storage time of the red cells is remarkably increased up to 42 to 49 days and the cellular contaminations (red cells and leucocytes in platelet concentrates, thrombocytes and leucocytes in FFP) are markedly diminished leading to a higher quality of these components. The Red Cross Blood Transfusion Service of Upper Austria presents its data obtained by the use of a quadruple plastic bag (RC Transfusion Production Center Eugendorf/Salzburg) with cellular contamination parameters far below the generally accepted limits. Apart from the increased quality of the components a very high level of clinical acceptance concerning especially the stored random platelet concentrates has been experienced. In conclusion the necessity of changing to a multiple bag system is strongly emphasized thus not only better fulfilling the clinical needs for the different blood components but also delivering higher qualities. Red cell preparations containing the buffy coat should therefore not be used any longer.

Blood Coagulation Factors↗
PubMed1991

[Standards for preclinical resuscitation--requirements for efficient therapy and scientific analysis. A prospective study using as an example the combined emergency medical service of the Munich administrative district and capital].

A standardized treatment protocol is essential for scientific evaluation of parameters influencing the outcome and survival of patients who have suffered cardiac arrest in a non-hospital situation. In addition, a standardized therapy algorithm permits effective, time-saving interaction of all members of the emergency team who work together to perform cardiopulmonary resuscitation (CPR) in any emergency outside the hospital. This paper gives the results obtained in 50 patients in whom on-the-spot resuscitation was performed by a specially trained team [emergency medical team (EMT) + on-scene physician] using an ACLS (advanced cardiac life support) protocol modified from the AHA (American Heart Association) standard. Two different algorithms were used one for ventricular fibrillation (VF) and pulseless ventricular tachycardia and one for asystole and pulseless bradycardia. When indicated, countershocks were first administered at a continuous energy level of 360 J, up to three times one after the other. All patients then received epinephrine intratracheally, 2 mg, immediately after intubation. In the case or persisting asystole a further 2-mg dose of epinephrine and then one 5-mg dose were given i.v. in keeping with the ACLS protocol. In the case of persisting VF or pulseless tachycardia we gave one 100-mg dose of lidocaine i.v. and then performed the next countershock at the same energy level. The time the team members actually needed for the single steps of the ACLS protocol was meticulously documented with the aid of a stop watch.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗
PubMed1990

Occurrence of infraslow potential oscillations in relation to task, ability to concentrate and intelligence.

The occurrence of infraslow potential oscillations (ISPOs) of the brain was investigated during a listening and a resting condition in 44 subjects (Ss) with high (HAC) and low ability to concentrate (LAC). The occurrence of ISPOs was found in 36% of the Ss. While in the HAC group the occurrence of ISPOs did not change from listening to resting, in the LAC group Ss with ISPOs were affected by experimental conditions, showing ISPOs during the listening condition. For Ss with ISPOs only during listening a lower score was found for ability to concentrate, suggesting ISPOs as a possible underlying mechanism. For Ss with stable ISPOs a higher I.Q. was found compared to Ss without ISPOs.

Adult↗
PubMed1989

Filtered dark-field and pure Z-contrast: two novel imaging modes in a Scanning Transmission Electron Microscope.

For the investigation of biological objects with a Scanning Transmission Electron Microscope (STEM) the dark-field imaging mode is the one used most often. We will show, regarding calculations that we have done which took into account the finite angle of the illumination and multiple scattering processes, that the collected amount of inelastically scattered electrons with an annular dark-field detector is higher then normally expected. According to the above calculations, we designed a new detection system to enable us to acquire three different images (inelastic, filtered dark-field and filtered bright-field) simultaneously.

Mathematics↗
PubMed1989

The electromyographic DC potential as a correlate of muscular activity.

The present experiment was undertaken to demonstrate the effect of muscular force as well as duration of muscular work on the electromyographic (EMG) DC potential. Thirty subjects had to lift different weights by flexing the right forearm within a defined and constant setting for 20 s. The experimental variables were weight (0.5, 1, 2, and 3 kg) and time. The EMG was recorded from the belly of the right biceps brachii muscle in a quasi-unipolar manner and split into an integrated ac channel (IEMG) and a dc channel (DC-EMG). The average IEMG showed a ramp-like shape. Analysis showed a positive relationship for weight (p less than 0.0001) and time (p less than 0.0001) with the IEMG. The average shape of the DC-EMG showed a negative initiation potential, a monotonically increasing negative potential during contraction (contraction potential), a positively peaking off potential and a slow return to baseline (after potential). Analyses of variance demonstrated a significant (p less than 0.001) relationship of weight to the magnitude of the initiation and the termination potential. Regression analyses displayed an inverse relationship of time to the termination (p less than 0.01) and to the resolution potential (p less than 0.001). The DC-EMG showed higher peaks (initiation and termination potential) for heavier weights. For the termination and after potential less positive deflections were found with increasing time (fatigue). A control condition (isometric contraction) indicated that the initiation, contraction, and termination potential of the DC-EMG may also be related to aspects of the movement. Results suggest that the DC-EMG is a more complex measure of muscular activity than the IEMG.

Adult↗