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Biomedical subjects

K Klein

Publications and source records attributed to K Klein.

At least 73 records · Page 4Linked to original sources
PubMed1993

Expression of Epstein-Barr virus nuclear antigen 1,2A and 2B in the baculovirus expression system: serological evaluation of human antibodies to these proteins.

The Epstein-Barr virus encoded nuclear antigens 1,2A, and 2B (EBNA 1, EBNA 2A, and EBNA 2B) were expressed in a baculovirus system. The full length recombinant proteins were recognized by polyclonal rabbit sera and by human sera. An immunofluorescence (IF) test for the differentiation between EBNA 1 and EBNA 2 antibodies in human sera was established with the expressed proteins. None of 55 sera of patients with infectious mononucleosis (IM) had anti-EBNA 1 antibodies while 36 of these sera had anti-EBNA 2A antibodies. Conversely, 47 of 51 sera from EBV-positive healthy carriers had anti-EBNA 1 antibodies and 18 of these sera had anti-EBNA 2A antibodies. The sensitivity and specificity of the EBNA 1 IF for the diagnosis of IM were higher as compared to conventional anti-complement immunofluorescence (ACIF). In the IF test differentiation between type A and type B EBV infection was only possible in sera from the IM patients. An immunoblot (IB) with low amounts of baculovirus expressed EBNA 2A and EBNA 2B antigen was carried out. Twenty-nine of 31 sera from IM patients or from healthy carriers with EBNA 2 antibodies reacted predominantly with EBNA 2A, whereas a known type B serum reacted strongly with EBNA 2B than with EBNA 2A.

Adolescent↗
PubMed1993

Overestimation of osteopenia using standard analysis software for peripheral quantitative computed tomography.

It is well established that measurement of bone mineral density (BMD) can estimate the risk of future fractures. To assess individual fracture risk BMD measurements are compared with a reference range provided by the manufacturer of the respective BMD technology. However, the power of trabecular bone measured by peripheral quantitative computed tomography (pQCT) to predict future fractures has not been shown up to now. We conducted measurements of trabecular bone density (TBD) at the distal radius (pQCT XCT 900, Stratec, Germany) in a sample of 506 healthy white women aged 40-60 years (mean 48) and compared the results with the manufacturer's normal range. We found a remarkable difference in TBD values between our healthy study population and the manufacturer's reference data in all age groups (e.g., age 50-54 years, 143.1 +/- 43.2 mg/cm3 versus 181.1 +/- 39.0 mg/cm3). Compared to the +/- 2 SD limits of the manufacturer's reference range our study population showed mean TBD values that were about 1 SD below the mean of the reference range. About 50% of our healthy cohort were below the -1 SD limit of the reference range. Almost ten times as many normal subjects as expected (22.1%) were found below the -2 SD limit and therefore classified as individuals with increased fracture risk. This overestimation of fracture risk leads to discomfort of the patient, unnecessary therapeutic intervention, and significant costs to the public.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Velocity of ultrasound at the patella: influence of age, menopause and estrogen replacement therapy.

Determination of apparent velocity of ultrasound (AVU) in bone has been proposed as a valuable tool for discriminating between normal and osteoporotic women. We have studied the influence of age, menopause and estrogen replacement therapy (ERT) on AVU at the patella in a large sample of pre- and postmenopausal women. Three hundred and eighteen woman aged 40-60 year participated in the study (112 women were premenopausal, 21 were perimenopausal and 185 were postmenopausal of whom 110 had received ERT for a minimum of 1 year). AVU was determined as the mean of four measurements at each patella using a Signet instrument (Osteo-Technology, Framingham, MA). An age-dependent decline in AVU was observed only after menopause (r = -0.33, p = 0.0055); in premenopausal women there was a slight but not significant decrease in AVU with age (r = -0.12, p > 0.05). AVU was significantly lower in postmenopausal women compared with premenopausal women (1882 +/- .84 m/s vs 1961 +/- 73 m/s, p < 0.05). ERT prevented the menopause-related fall in AVU. There was a significant positive correlation between the duration of ERT and AVU measurements. Our findings demonstrate a pronounced influence of estrogens on AVU at the patella, supporting the concept of a protective role of ERT in bone stability. AVU measurements therefore merit further investigation as an inexpensive method for predicting fracture risk that does not expose the subject to radiation.

Adult↗
PubMed1993

Apparent velocity of ultrasound (AVU) at the patella in comparison to bone mineral density at the lumbar spine in normal males and females.

It has been reported that apparent velocity of ultrasound (AVU) at the patella discriminates as well between osteoporotic and normal subjects as measurement of bone mineral density (BMD) using dual photon absorptiometry. To investigate the relationship between AVU and peak bone mass, we compared AVU (Signet, Osteo-Technology, Framingham, MA) at the patella and BMD (QDR 1000, Hologic, Waltham, MA) at the lumbar spine in a large sample of healthy males and females. The study population consisted of 153 males (aged 20-60 years) and 129 premenopausal females (aged 20-52 years). Vertebral BMD showed no significant difference between males and females (1.03 +/- 0.16 g/cm2 for males vs. 1.07 +/- 0.14 g/cm2 for females, NS), while AVU values were significantly higher in males compared with females (1967 +/- 64 m/s vs. 1938 +/- 76 m/s, P < 0.05). In men there was a significant decrease in BMD with aging (r = -0.27, P < 0.05), in premenopausal females we found no age-related change in BMD. Similarly in males AVU decreased significantly with age (r = -0.2, P < 0.05), whereas in females AVU values showed relative stability over the age range. There was a significant correlation between AVU and BMD (r = 0.36 for males, r = 0.34 for females, P < 0.05). Our study demonstrates only a weak correlation between AVU at that patella and BMD at the lumbar spine, supporting the view that AVU not only reflects bone quantity but possibly also qualitative properties of bone structure. The sex difference in AVU but not in BMD suggests that the trabecular bone at the patella differs significantly from axial trabecular bone. The identical peak BMD at the lumbar spine for young males and females underscores the importance of the menopause for later manifestation of vertebral fractures.

Absorptiometry, Photon↗
PubMed1992

Effect of instructions on isokinetic trunk strength testing variability, reliability, absolute value, and predictive validity.

Although isokinetic strength testing has been in use for more than two decades, and numerous studies have addressed isokinetic performance of the lumbar spine, the effect of instructions on isokinetic trunk strength has not been studied. In a sample of 30 healthy women, this study examined the effect of "high-demand" instructions on lumbar strength performance. High-demand instructions were found to have a substantial positive effect on performance variability, reliability, absolute magnitude, and validity. Under these conditions, isokinetic trunk strength was found to be predictive of performance in a frequent lifting-lowering task.

Adult↗
PubMed1992

Patient education programmes in obstructive airway disease. The Ingelheim Model for promoting health through patient education.

Chronic obstructive airway diseases (COAD) can be regarded as one of the major health problems needing environmental actions and screening programs for early detection and intensive patient education programs to cope with the needs of tertiary prevention. On the basis of our epidemiological study focused on COAD carried out in FRG (sample size August 1988: 63,000 participants) a patient education program has been developed and evaluated. In cooperation with general practitioners and pneumologists the program has been installed at practice and community level. The need for a patient education program has been assessed during the three years of the PNEUMOBIL-Project. It is not just a matter of cutting costs, but to a large extent a matter of the wellbeing of the patients and of reducing side effects to a minimum. The objective of the project can be split into three dimensions: (1) The cognitive aspect. Here significant lack of knowledge has to be overcome. At this point it has to be stated clearly that at the present time the medical community is not able to solve this problem on their own. (2) The psychomotoric aspect. Here the competent use of medication has to be trained. (3) The emotional aspect. The patient has to be motivated and integrated into the therapeutic process in a way that his compliance contributes significantly. The didactical concept consists of modules that can be used in varying sequences according to the needs of the target audience.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Obstruction↗
PubMed1992

[Reproducibility of bone density measurements of the distal radius using a high resolution special scanner for peripheral quantitative computed tomography (Single Energy PQCT)].

Reliable determination of bone loss in the skeletal system depends on the accuracy of bone mineral density (BMD) measurements. We investigated short-term and long-term accuracy in vitro and in vivo using a new, commercially available special-purpose computed tomography scanner (Single Energy Peripheral QCT: XCT 900, Stratec FRG) for BMD measurements. Using a phantom, the long-term accuracy (3 months) in vitro yielded a coefficient of variation (cv) of 0.18%. Repeated measurements in 37 patients showed excellent reproducibility, with a cv of 0.71%. The differentiation into groups of low, average and high trabecular bone density demonstrated values of 0.61%, 0.59% and 0.98%, respectively for cv. BMD determination with pQCT is a high-precision method. It seems to be suitable for detection of trabecular bone loss in the range of the annual decrease in bone mass, provided the forearm is positioned with maximum care.

Bone Density↗
PubMed1991

Glutathione levels during thermal induction of the yeast-to-mycelial transition in Candida albicans.

Glutathione (GSH) levels were directly monitored by reverse phase HPLC during the thermal yeast-to-mycelial induction of Candida albicans. The GSH levels decreased approximately 100-fold within 120 min which corresponded to the time of maximal yeast-to-mold conversion. The yeast to mold conversion was inhibited by 1-p-chlorophenyl-4,4-dimethyl-5-diethylamino-1-penten-3-one (CDDP), a thiol-specific alkylator, which prevented the decline in GSH levels. These results are discussed with respect to the potential involvement of intracellular GSH levels in regulation of the yeast-to-mold dimorphism in Candida albicans.

Candida albicans↗
PubMed1990

Differential gene expression of IFN-alpha and tumor necrosis factor-alpha in peripheral blood mononuclear cells from patients with AIDS related complex and AIDS.

Human PBMC from HIV-1-infected individuals produced ex vivo in response to vesicular stomatitis virus only low amounts of IFN-alpha. This impairment was significant as early as Walter Reed (WR) stage 2; at WR stage 4-5, the production was almost zero. At WR stage 2 of infection, IFN-alpha mRNA was exclusively found in association with polyribosomes, indicating that IFN-alpha gene was transcriptionally inactive under the experimental conditions used. A similar decrease of the level of transcripts as a function of the progression of the disease was also observed for the IFN-gamma mRNA. In contrast, TNF-alpha production was strongly enhanced in PBMC from HIV-1-infected individuals after stimulation with LPS compared to the TNF-alpha production of activated PBMC from healthy donors. Almost parallel with the increase of the level of the transcript for TNF-alpha, the level of TNF-beta increases as well. Data are presented which show that the increased TNF-alpha production is due to a longer half-life of TNF-alpha transcripts in PBMC from infected individuals. These results let us suggest that the up-regulation of TNF-alpha gene expression in PBMC from HIV-infected individuals is controlled predominantly on the posttranscriptional level, whereas transcriptional events regulate the level of IFN-alpha transcripts. This assumption is supported by run-on experiments which revealed that the extent of transcription of TNF-alpha gene is almost identical in nuclei from stimulated PBMC of noninfected and HIV-infected donors, whereas the transcription of IFN-alpha gene is strongly suppressed in nuclei from HIV-infected individuals at WR stages 3 and 6.

AIDS-Related Complex↗
PubMed1990

Preserved recognition of familiar personal names in global aphasia.

Recognition of proper and common nouns was compared in four patients diagnosed with global aphasia secondary to ischemic left-hemisphere infarction. For proper noun recognition, subjects matched the spoken or written name of a famous person to a photograph, and for common nouns, subjects were tested on standardized and special word recognition tests. As expected, common noun recognition was severely compromised in the aphasic patients. In contrast, familiar personal names, despite their greater length and complexity, were recognized equally well by aphasic and normal control subjects. The right hemisphere may mediate the ability to recognize personally familiar names, as it may be specialized for establishing personally relevant environmental stimuli.

Aged↗
PubMed1990

Do instructions modify effects of beta-adrenoceptor blockade on anxiety?

To study the interaction between physiological and cognitive factors in anxiety, 44 subjects with public speaking anxiety were allocated to four different groups. Two groups received either beta-adrenoceptor blockade (100 mg of atenolol) or placebo orthogonally crossed with an instruction that heart rate would decrease or an instruction that did not mention cardiovascular effects. During the delivery of a speech, measures of heart rate, systolic and diastolic blood pressures, and self-reported anxiety were obtained. All variables increased during an anticipation period before speech, and heart rate, systolic blood pressure, and self-reported anxiety increased further during speech. Regardless of instructions, atenolol decreased heart rate and systolic blood pressure during both anticipation and speech, whereas no differences were found in self-reported anxiety. This lack of a relationship was seen in spite of the correctly perceived heart rate reduction in the atenolol-treated group receiving an instruction that heart rate would decrease. Cardiac aware subjects, according to the Autonomic Perception Questionnaire, showed higher levels of heart rate and self-reported anxiety at rest than did cardiac unaware subjects. During speech, even though heart rate was similar in atenolol treated groups, self-reported anxiety was higher in cardiac aware than in cardiac unaware subjects. The lack of a relationship between heart rate and self-reported anxiety is discussed in terms of primary and secondary emotions. It is suggested that the perception of external rather than internal cues determines situationally elicited anxiety.

Adult↗
PubMed1990

Decision strategies in neuropsychology II: determination of age effects on neuropsychological performance.

The relationship of age to neuropsychological test performance was explored on the subtests comprising the Halstead-Reitan Battery and allied tests. Performance of 192 pseudo-neurologic control patients across 10-year age intervals from 16 to 65 was analyzed. The findings indicate a strong age-performance effect on spatial and more complex integrative tests with peak performance between 25 to 35 years of age and a decline thereafter. A lack of significant decline was noted on sensory, motor, and language tasks. The findings reveal that there is a curvilinear change in performance as a function of age and were discussed with regard to the obvious need to modify decision strategies to account for the age of the patient.

Journal Article↗
PubMed1989

Phase II trial of a new biological response modifier (ImuVert) in advanced prostate cancer.

ImuVert, a new biological response modifier of bacterial origin, was evaluated in a Phase II trial of patients with metastatic prostate cancer. Sixteen patients with hormone refractory measurable or evaluable disease were treated with ImuVert 1.0 mg subcutaneously once weekly for 5 weeks. After a 1 week rest period, the dose was escalated to 3.0 mg weekly for 5 additional weeks. Eleven patients received the full 10 weeks of therapy. Toxicity consisted of mild transient flu-like symptoms as well as the development of tenderness and induration at injection sites. No patient responded to treatment. ImuVert at this dose and schedule is inactive in advanced prostate cancer.

Aged↗
PubMed1989

Effects of acute alcohol ingestion on the left ventricular performance of normal subjects before and after incomplete autonomic blockade.

The effects of acute alcohol ingestion on the left ventricular performance of nine normal subjects, mean age 25 years, were studied before and after incomplete autonomic blockade, produced by atropine, 0.04 mg/kg body weight, and propranolol, 0.2 mg/kg body weight. Left ventricular (LV) function curves (stroke volume vs. end-diastolic volume) were plotted from data generated before and after large variations in cardiac preload. Increase in preload was produced by five degrees of head-down tilt for 90 minutes; decrease in preload was produced by graduated lower body negative pressure to -40 mmHg. After incomplete autonomic blockade, the negative inotropic effects of acute alcohol ingestion were minimal but significant and manifest by the reduction in mean velocity of circumferential fiber shortening (p less than 0.05). Studies during wide variations in preload confirmed the importance of maintaining central blood volume after alcohol ingestion. Lower body negative pressure after both incomplete autonomic blockade and alcohol produced a further deterioration in mean velocity of circumferential fiber shortening (p less than 0.05).

Adult↗
PubMed1989

[The value of sonography in salivary gland tumors].

In a prospective study, 178 patients with tumours of the salivary glands were examined both clinically and by ultrasound. All patients have since been operated upon, and the diagnosis was confirmed histologically. The diagnostic accuracy of clinical examination is compared with that of ultrasound. Every tumour of the salivary glands could be diagnosed by ultrasound. In the benign group, an exact diagnosis of the tumour type was possible in 83% of cases. In the malignant group an exact diagnosis was only possible in 57% of cases. Furthermore, it is possible with ultrasound to recognise multiple and bilateral tumours, to determine whether a tumour is intra- or extraglandular, and to show the nature of the tumour (cyst, abscess, central necrosis) to a much greater extent than with clinical examination alone. In addition, a fairly good assessment of the cervical and intraglandular lymph nodes is obtained. We believe that ultrasound is of great importance in the diagnosis of tumours of the salivary glands.

Adenolymphoma↗
PubMed1988

Inhibitors of collagenase IV and cell adhesion reduce the invasive activity of malignant tumour cells.

The invasive activities of some malignant cells appear to be activated by contact with laminin. This protein occurs solely in basement membranes and the binding of malignant cells to the surface of this extracellular matrix initiates the invasion process. Passage of the cells across basement membrane requires degradative activity and laminin induces the production of collagenase IV which lyses the collagen IV network. The motility of the cells is enhanced by chemo-attractants and by matrix molecules. Peptides that inhibit the binding of tumour cells to laminin, inhibitors of collagenase IV, and inhibitors of specific pathways of arachidonic acid metabolism prevent invasion as well as the metastasis of malignant cells and could be employed to stop the spread of cancer.

Animals↗
PubMed1987

Adolescents' compliance with the use of oral contraceptives.

To elucidate the factors that might influence compliance with oral contraceptive use among sexually active adolescents, we undertook a study of 209 unmarried adolescents initiating use of oral contraceptives in three different settings: an inner-city adolescent clinic, a birth control clinic in a midsized industrial city, and a suburban private practice. At the three-month follow-up visit, factors associated with compliance included older age, suburban residence, white race, health care in the suburban private practice, payment status, prior use of contraception, mother's unawareness of oral contraceptives, married parents, older boyfriend, lack of worry about being pregnant, and satisfaction with pill use. Compliance at long-term follow-up (13.5 +/- 3.7 months) was additionally associated with educational goals, father's education level, and absence of side effects. Ten pregnancies occurred during the study period among noncompliant site I patients. Inner-city clinic patients were at high risk of noncompliance and unplanned pregnancy.

Adolescent↗