Biomedical subjects
Publications and source records attributed to K Schmidt.
Transcranial Doppler sonography is described and recommended as being well suited for the continuous monitoring of neurosurgical intensive-care patients parallel to ECG monitoring. The article discusses the problems involved with both methods, their efficiency possible risks of application (damaging of immobile tissue situated within the ultrasonic beam).
We analysed cumulative disease frequencies in the first 231 adult Danish AIDS patients with life tables. There was a certain hierarchical pattern in the occurrence of complicating diseases. Herpes zoster, Kaposi's sarcoma and Pneumocystis carinii pneumonia were early manifestations, whereas diseases caused by cytomegalovirus and atypical mycobacteria tended to occur later in the course of AIDS. Compared with all other AIDS patients, homosexual men were more likely to develop Kaposi's sarcoma, cytomegalovirus chorioretinitis and mucocutaneous herpes simplex virus infection. The proportion of patients who developed particular diseases changed with calendar time. Most striking was a three to fourfold decrease in diseases caused by cytomegalovirus. In conclusion, the study showed that disease frequencies in patients with AIDS may vary with the patients risk behaviour and duration of AIDS, and that the frequencies of particular diseases may change with calendar time.
Length of survival was analysed in relation to year of diagnosis, AIDS-indicative disease, age, risk behaviour, zidovudine therapy, and CD4 cell count and serum immunoglobulin (Ig) levels at the time of diagnosis in a group of 231 consecutive adult Danish AIDS patients reported before 1 January 1988. The cumulative survival rate was 53% (95% confidence interval 47-59%) at 1 year, 29% (22-36%) at 2 years and 18% (10-26%) at 3 years. Length of survival increased significantly (P less than 0.001) over time for patients who were initially diagnosed with Pneumocystis carinii pneumonia (PCP), 17% (3-31%) at 2 years prior to 1986, 32% (16-49%) in 1986 and 52% (34-69%) in 1987, whereas survival remained stable for patients with other AIDS-indicative diseases. Survival was similar for patients who were diagnosed with Kaposi's sarcoma alone and PCP alone. Independent predictors of a shortened survival were a CD4 cell count less than 200 x 10(6)/l, a serum IgA level greater than 4 g/l, and an initial diagnosis with opportunistic infections other than PCP. In addition, the multivariate analysis suggested an improved survival in recent years for patients diagnosed with PCP, independent of other factors examined. We conclude that length of survival in AIDS patients is highly variable. Determinants of progression include CD4 cell count, serum IgA level, and presenting disease. Survival has increased markedly for patients with PCP and median survival now exceeds 24 months.
This report describes the course of psychiatric illness in two boys. Both presented with attention deficit hyperactivity disorder (ADHD) in midchildhood; after puberty, one boy developed a schizophrenic illness while the other boy developed a major affective illness. Although the major ADHD outcome studies have found no link between the childhood occurrence of ADHD and psychosis in adulthood, occasionally such a link may exist. The theoretical and practical implications of this finding are discussed. It should be noted, however, that such outcome is highly atypical and very rare.
The time course and magnitude of the effects of product loss on the measurement of local cerebral glucose utilization (LCGU) by the 2-[14C]deoxyglucose (DG) method were studied by determination of LCGU in 38 rats with 25-120 min experimental periods after a [14C]DG pulse and in 45 rats with experimental periods of 2.5-120 min during which arterial plasma [14C]DG concentrations (C*P) were maintained constant. LCGU was calculated by the operational equation, which assumes no product loss, with the original set of rate constants and with a new set redetermined in the rats used in the present study; in each case the rate constants were those specific to the structure. Data on local tissue 14C concentrations and C*P were also plotted according to the multiple time/graphic evaluation technique ("Patlak Plot"). The results show that with both pulse and constant arterial inputs of [14C]DG the influence of the rate constants is critical early after onset of tracer administration but diminishes with time and becomes relatively minor by 30 min. After a [14C]DG pulse calculated LCGU remains constant between 25 and 45 min, indicating a negligible effect of product loss during that period; at 60 min it begins to fall and declines progressively with increasing time, indicating that product loss has become significant. When C*P is maintained constant, calculated LCGU does not change significantly over the full 120 min. The "Patlak Plots" reinforced the conclusions drawn from the time courses of calculated LCGU; evidence for loss of product was undetectable for at least 45 min after a pulse of [14C]DG and for at least 60 min after onset of a constant arterial input of [14C]DG.
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Respiratory cryptosporidiosis is a rare complication of intestinal infection by cryptosporidia, with only six cases reported (to our knowledge) since its first description in 1983. We report the first case of respiratory cryptosporidiosis recognized at the National Institutes of Health, Bethesda, Md. An antemortem diagnosis was made based on recognition of acid-fast cryptosporidia in an induced sputum specimen obtained from a 64-year-old woman with malignant lymphoma and an associated profound immunodeficiency. Autopsy confirmed the presence of cryptosporidia along the apical aspect of the respiratory epithelium lining the trachea, bronchi, and bronchioles. Cryptosporidia were also identified in the duodenum and gallbladder. Immunohistochemical staining of the paraffin-embedded autopsy lung sections using a monoclonal antibody verified the diagnosis of cryptosporidiosis. Review of our case and the literature suggests that respiratory cryptosporidiosis is characterized by a chronic tracheitis, bronchitis, and bronchiolitis but generally does not cause severe pulmonary dysfunction.
In a double-blind clinical trial, a total of 463 volunteers were enrolled in a study designed to compare the effects of zinc gluconate lozenges (4.5 mg zinc) and a placebo for common cold. The tablets were to be taken every 1-1 1/2 waking hours at the first symptoms and for the following days until the common cold was over, but for no longer than 10 days. During the winter months of 1987 and 1988, 145 experienced a common cold and 130 completed the study. For final analysis, 61 patients in the zinc lozenge group and 69 patients in the placebo lozenge group were evaluated. Based on the patients' records the duration and severity of the common cold were compared. No statistically significant differences were found between the patient groups. Two recent studies using a five-time higher zinc dose per lozenge for common cold showed a significant, positive effect, but associated with frequent side-effects, first of all taste distortion. In the present study there was a weak tendency (not statistically significant, p = 0.12) towards more patients in the zinc lozenge group than in the placebo lozenge group reporting side-effects.
Seven genetic marker systems were analyzed from liquid blood and dried bloodstain specimens submitted to the Nebraska State Patrol Crime Laboratory from various law enforcement agencies throughout Nebraska. The phenotypic and genotypic frequencies for the ABO, Lewis, esterase D (ESD), phosphoglucomutase (PGM), adenylate kinase (AK), adenosine deaminase (ADA), and haptoglobin (HP) systems were calculated. The results indicate that the phenotypic frequencies are generally in agreement with frequencies reported in other populations in the United States.
In 46 patients with a suspected history of food allergy, we performed scratch tests using commercial food extracts (CF) in comparison with natural food products (NF). We found that NF brought about significantly stronger reactions than CF: 77% of the skin tests with NF were positive, whereas 75% of the tests with CF equivalents yielded negative or questionably positive results. We conclude, therefore, that in case of suspected food allergy, testing with CF only is not sufficient.
Various stimulants of the release of EDRF (endothelium-derived relaxing factor) increased intracellular cGMP levels in bovine aortic endothelial cells. ATP was the most effective compound tested, increasing cGMP 7-fold, followed by the calcium ionophore, A23187 (4.8-fold), and bradykinin (4.0-fold). The EC50 values were similar to those obtained when EDRF release was measured with the bioassay technique, which suggests a stimulation of endothelial guanylate cyclase by EDRF. The direct acting stimulants of soluble guanylate cyclase, sodium nitroprusside and SIN-1 (3-morpholino-sydnonimine), also increased the cGMP content of endothelial cells by 9.4 and 7.2 times, respectively. The effects of both groups of stimulants on cGMP levels were antagonized by the lipoxygenase inhibitor, nordihydroguaiaretic acid, and by the radical scavenger, phenylbutylnitrone, whereas gossypol or canavanine only antagonized the EDRF-induced effect on endothelial cGMP levels. Bradykinin, ATP and A23187 also increased the uptake of 45CaCl2 into endothelial cells but since the complete removal of extracellular Ca2+ or blockade of Ca2+ transport by LaCl3 did not affect the ability of these compounds to elevate cGMP levels, the formation of EDRF appears not to be triggered by an influx of extracellular calcium. This study provides evidence that EDRF stimulators enhance cGMP levels in endothelial cells, probably due to a direct activation of guanylate cyclase by EDRF.
In the presence of porcine aortic endothelial cytosol, soluble guanylyl cyclase purified from bovine lung was activated by L-arginine up to 2.5-fold, with an EC50 of about 6 microM. This activation was dependent on NADPH and Ca2+. The EC50 for Ca2+ was about 60 nM. No effect of L-arginine on guanylyl cyclase was observed when the cytosolic proteins were heat-denaturated. The effect of L-arginine was inhibited by NG-monomethyl-L-arginine and hemoglobin. These results indicate that endothelial cells contain a cytosolic enzyme which is directly or indirectly regulated by Ca2+ and converts L-arginine into a compound which in stimulating soluble guanylyl cyclase behaves similar to endothelium-derived relaxing factor.
The activity of the interferon inducible enzyme 2'-5' oligoadenylate synthetase (2-5A synthetase, E.C. 2.7.7) which converts ATP into a series of 2'-5' oligoadenylates was measured using analytical capillary isotachophoresis. The turnover rate of ATP during the reaction was monitored by determination of its concentration at the beginning and the end of the 2-5A synthetase reaction. The enzyme was analysed in extracts of peripheral blood mononuclear cells either pretreated or not with interferon.
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Alcohol extracts from the frog Atelopus oxyrhynchus were toxic to mice when injected intraperitoneally. The toxin was purified by gel filtration on a Sephadex G-15 column, and was identified as tetrodotoxin by thin-layer chromatography and GC-MS analysis of the alkali-hydrolyzed and trimethylsilylated derivative giving the same pattern as the C9-base of tetrodotoxin.
In 1986, 1711 nymphal and adult Ixodes ricinus orginating from Berlin (West) forests were examined individually or in pools of up to 10 ticks for the presence of Borrelia burgdorferi, the etiologic agent of Lyme borreliosis. Detection of borreliae was carried out by means of a culture method using modified Barbour-Stoenner-Kelly-Medium (BSK II). Tick populations from 14 out of 15 locations contained positive specimens. The calculated minimal infection rate of pooled ticks was 2.5% in nymphs (n = 1365), 10.2% in females (n = 59), and 5.3% in males (n = 114). Among those ticks examined individually, none of the nymphs (n = 49) proved to be positive but B. burgdorferi was isolated from 8.2% of the females (n = 73) and 7.8% of the males (n = 51). Fifty-five out of 56 isolates were identified as B. burgdorferi by means of an indirect immunofluorescence test (IFT) using monoclonal antibody H 5332. From these results B. burgdorferi must be considered as being present in the Berlin area.
A translocase to transport hexose phosphate formed in the cytosol into the cisterns of the endoplasmic reticulum, where the phosphatase resides, is absent in brain (Fishman and Karnovsky, 1986). 2-Deoxyglucose-6-phosphate (DG-6-P) may therefore have limited access to glucose-6-phosphatase (G-6-Pase), and transport of the DG-6-P across the endoplasmic reticular membrane may be rate limiting to its dephosphorylation. To take this compartmentation into account, a five-rate constant (5K) model was developed to describe the kinetic behavior of 2-deoxyglucose (DG) and its phosphorylated product in brain. Loss of DG-6-P was modeled as a two-step process: (a) transfer of DG-6-P from the cytosol into the cisterns of the endoplasmic reticulum; (b) hydrolysis of DG-6-P by G-6-Pase and subsequent return of the free DG to the precursor pool. Local CMRglc (LCMRglc) was calculated in the rat on the basis of this model and compared with values calculated on the basis of the three-rate constant (3K) and the four-rate constant (4K) models of the DG method. The results show that under normal physiological conditions all three models yield values of LCMRglc that are essentially equivalent for experimental periods between 25 and 45 min. Therefore, the simplest model, the 3K model, is sufficient. For experimental periods from 60 to 120 min, the 4K and 5K models do not correct completely for loss of product, but the 5K model does yield estimates of LCMRglc that are closer to the values at 45 min than those obtained with the 3K and 4K models.