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Biomedical subjects

J Stein

Publications and source records attributed to J Stein.

At least 19 recordsLinked to original sources
PubMed1992

Simple and rapid method for determination of short-chain fatty acids in biological materials by high-performance liquid chromatography with ultraviolet detection.

A new and versatile method for the identification and quantification of short-chain fatty acids, such as formic, acetic, propionic, butyric, isobutyric, valeric, isovaleric and mercaptoacetic acids, in biological specimens by high-performance liquid chromatography is described. After sample purification by vacuum transfer and concentration by alkaline freeze-drying, the acids were measured without any further preparative step, using a sulphonated polystyrene-divinylbenzene column as stationary phase. Ultraviolet detection of the native acids was done at 214 nm. Peak resolution and reproducibility were as good as with gas chromatography. Many examples of the application of this method to a variety of biological specimens and fluids both from the rats and humans are described.

Animals↗
PubMed1992

Favorable experience with pre-emptive renal transplantation in children.

We retrospectively examined our experience with live-related donor kidney transplants in 66 children during the 7-year period 1984-1990. We compared the clinical courses of 26 children who did not receive any dialytic therapy prior to transplantation with 40 children who were dialyzed (27 via peritoneal dialysis and 13 via hemodialysis). We did not find any statistically significant differences in patient or graft survival between these three groups with a follow-up period of 6-87 months. Based on our results, we conclude that pre-emptive transplantation is an acceptable treatment for children who will inevitably require renal replacement therapy.

Adolescent↗
PubMed1992

Desensitization to allopurinol in patients with gout and cutaneous reactions.

PURPOSE: To determine the efficacy and safety of slow oral desensitization in the management of allopurinol-related pruritic cutaneous eruptions. PATIENTS AND METHODS: Nine patients with renal insufficiency and chronic tophaceous gouty arthritis, who had to interrupt their allopurinol therapy because of an allergic-type pruritic maculopapular eruption, were enrolled in an allopurinol oral desensitization protocol using a schedule of gradually increasing doses. RESULTS: Cautious reinstitution of allopurinol was successfully accomplished in all nine patients, but four individuals required dose adjustment because of development of a mild, recurrent, macular rash early during the protocol at allopurinol doses of less than or equal to 5 mg/d. Transient, postdesensitization cutaneous reactions occurred in two patients, one of whom also had an early rash. CONCLUSION: Oral desensitization to the minor rashes induced by allopurinol is a feasible and acceptably safe approach to therapy, particularly for those with renal insufficiency in whom no substitute urate-lowering drug is available.

Administration, Oral↗
PubMed1992

High-performance liquid chromatographic determination of biotin in biological materials after crown ether-catalyzed fluorescence derivatization with panacyl bromide.

This paper reports a high-performance liquid chromatographic (HPLC) technique to determine biotin in biological samples. Biotin and the internal standard dethiobiotin are converted into fluorescent derivatives by using panacyl bromide [p-(9-anthroyloxy)phenacyl bromide] as a fluorescence label. Biotin is extracted from biological tissue with trichloroacetic acid and the extract is purified by a combination of solid-phase extraction on C18 cartridges, ion-exchange chromatography on DOWEX formate resin, and thin-layer chromatography. The purified sample extract is derivatized in the presence of a crown ether. The resulting panacyl esters can be separated on reversed-phase as well as on normal-phase HPLC. Normal phase HPLC is preferable because it provides higher sensitivity and demands less sample pretreatment. Analysis of rat intestinal tissue revealed that only about 13% of the biotin is present in free form whereas 87% is bound in proteins from which it can be released by hydrolysis. Biotin values determined by this method are comparable to those obtained by other techniques.

Acetophenones↗
PubMed1992

Studies on the ecology of Lyme disease in a deer forest in County Galway, Ireland.

The abundance of the tick Ixodes ricinus (L.) and the infection rate of ticks with Borrelia burgdorferi (Johnson et al.) were compared on either side of a deer fence in a forest park in County Galway, Ireland, in an attempt to elucidate the role of fallow deer, Dama dama, and woodmice, Apodemus sylvaticus, in determining the population density of I. ricinus and the transmission of B. burgdorferi. The results showed that tick numbers were much higher on the deer side of the fence, although the density of mice was similar on both sides. This suggests that, in the absence of other obvious factors, deer rather than mice are responsible for tick abundance in this habitat. Tick infection rates, determined by immunofluorescence, were consistently higher outside the deer fence than inside it. It is suggested, therefore, that mice rather than deer may be the important reservoir hosts of B. burgdorferi in this habitat and that deer, by feeding many larvae, probably contribute large numbers of uninfected ticks to the population. If this is the case, there will not be a direct relationship between deer abundance and tick infection rates. This has important implications for risk assessment.

Animals↗
PubMed1992

Spinal cord arteriovenous malformation in a person with congenital lymphatic abnormalities.

Spinal cord arteriovenous malformations have been described in association with a variety of congenital diseases affecting the vasculature, including Klippel-Trenaunay-Weber syndrome, Rendu-Osler-Weber syndrome and others, but rarely in association with lymphatic abnormalities. We report the case of a young man with congenital lymphedema and arteriovenous malformations of one lower extremity and a spinal cord arteriovenous malformation. Awareness of the possible presence of a central nervous system arteriovenous malformation in individuals with pre-existing arteriovenous and lymphatic abnormalities may be helpful in their diagnosis and management.

Abnormalities, Multiple↗
PubMed1992

Tick infection rates with Borrelia: Ixodes ricinus versus Haemaphysalis concinna and Dermacentor reticulatus in two locations in eastern Germany.

Unfed nymphal Ixodes ricinus, Haemaphysalis concinna, and adult Dermacentor reticulatus were collected in two locations of Saxony in July and September 1991 by flagging. In July, the abundance of nymphal I. ricinus was about 2-3 times higher than that of nymphal H. concinna, a time of the year when nymphs of both species are reported to have a seasonal peak of activity. No D. reticulatus were flagged concurrently. In September, host-seeking activity of nymphal I. ricinus was again quite high as was that of adult D. reticulatus but only low numbers of nymphal H. concinna were collected. The flagged ticks were individually examined for Borrelia by an indirect immunofluorescence assay (I. ricinus: n = 414; H. concinna: n = 96; D. reticulatus: n = 116). The prevalence of Borrelia (probably B. burgdorferi) in I. ricinus varied from 12.1% to 21.0%. No borreliae were found in H. concinna. Of the examined D. reticulatus from one site (n = 97) 11.3% contained either B. burgdorferi or a related Borrelia. This may be the first finding of Borrelia in an Eurasian Dermacentor species.

Animals↗
PubMed1992

Covering one eye affects how some children read.

The Dunlop Test was used to identify unstable binocular control in a group of 32 mixed-ability children. They were compared with 32 reading age-matched controls. The children were then asked to read two lists of single real words of equal linguistic difficulty: one with both eyes open and the other with the left eye occluded. Only children who failed the Dunlop Test made fewer non-word errors when they read with one eye. This result provides additional support for the theory that unstable binocular control can directly affect how children read. In addition, these findings suggest that this effect must be due, at least in part, to some interaction between the images from the two eyes.

Child↗
PubMed1992

Characteristics of putrescine uptake by human brush border membrane vesicles.

Both putrescine and the polyamines spermidine and spermine are essential factors for growth and differentiation in all cells of higher eucaryotes. In principle, increased requirements of polyamines in mucosal cells either can be met by de novo-synthesis or by increasing the uptake from lumen (brush border membrane) or bloodstream (basolateral membrane). We therefore evaluated putrescine uptake in intestinal mucosal cells by using human brush border membrane vesicles (BBMV). Intravesicular uptake of putrescine was shown by osmoplots. This process was not saturable over a substrate range from 1 to 80 microM. Putrescine transport was also found to be independent of temperature (Q10 = 1.23). No differences in putrescine uptake rates were found in the presence or absence of Na+, and there was no evidence for any dependence of putrescine uptake from other cations. Our data indicate that putrescine uptake by human intestinal brush border membrane vesicles occurs by passive diffusion. It is concluded that a formerly described saturable and carrier mediated uptake in isolated intestinal mucosal cells from different species is probably influenced by active transport across the basolateral membranes. Therefore, further studies with isolated basolateral membranes are advocated.

Cell Membrane↗
PubMed1991

Isolation and characterization of a cDNA from a human histone H2B gene which is reciprocally expressed in relation to replication-dependent H2B histone genes during HL60 cell differentiation.

A variant human histone H2B cDNA (HHC289) has been cloned and characterized and shown to have a complex pattern of regulation with respect to the HeLa S3 cell cycle and HL60 cell differentiation. The H2B protein coding region of HHC289 is flanked at the 3' end by a 1798-nt nontranslated trailer that contains a region of hyphenated dyad symmetry and a poly(A) addition sequence, followed by a poly(A) tail. Nuclear run-on transcription analysis revealed a 2-fold increase in transcription of the HHC289 gene during S phase, in comparison to replication-dependent human histone genes which exhibit a 2-3-fold increase in transcription during S phase. Northern blot analysis indicated that the levels of the 2300-nt HHC289 mRNA species did not vary significantly during the HeLa S3 cell cycle, in comparison to replication-dependent H2B mRNAs which are elevated 15-fold during S phase. Northern blot analysis also revealed a reciprocal relationship during the onset of HL60 differentiation between the expression of the HHC289 H2B gene and the replication-dependent H2B genes. The levels of the 2300-nt HHC289 H2B species increased approximately 10-fold during HL60 cell differentiation whereas the levels of cell cycle dependent H2B mRNAs decreased to less than 1% of those in proliferating cells. These results suggest that complex transcriptional and posttranscriptional regulatory mechanisms control cellular levels of mRNAs from various human H2B histone genes during progression through the cell cycle and at the onset of differentiation.

Amino Acid Sequence↗
PubMed1991

Disruption of the cytoskeleton with cytochalasin D induces c-fos gene expression.

The treatment of exponentially growing HeLa cells and quiescent WI-38 cells with cytochalasin D, which disrupts the cytoskeletal microfilaments, results in a rapid and marked increase in the transcription of the c-fos protooncogene with a concomitant increase in c-fos mRNA steady-state levels. Transcription of rRNA, HLA-B7, and H4 histone genes was not significantly affected by the drug treatment. These results suggest that the nucleus can respond to signals related to the structural organization of the cytoskeleton and selectively adjust the regulation of gene expression.

Cytochalasin D↗
PubMed1991

Paradoxical movement in Parkinson's disease.

Patients with Parkinson's disease, although impaired, can sometimes move effectively under visual guidance. The stimuli that often elicit such paradoxical movement are similar to those that relay visual information to the cerebellum. We suggest that many instances of paradoxical movement may be explained by the fact that the pathways relaying those visual stimuli can bypass the damaged basal ganglia and allow an intact cerebellar circuit to be used for visuomotor control.

Cerebellum↗
PubMed1991

The expression of epidermal growth factor receptor on human bladder cancer: potential use in radioimmunoscintigraphy.

Monoclonal antibody 425, which binds to an extracellular domain of the epidermal growth factor receptor, was used to evaluate the expression of this antigen on bladder cancer cells. Epidermal growth factor receptor was found on all bladder cancer cell lines tested. Immunoperoxidase staining of fourteen invasive human bladder cancers with monoclonal antibody 425 demonstrated that ten showed strong staining, one showed weak staining and three were negative. Five noninvasive tumors were similarly examined. Four of these were negative and one showed weak staining. Biodistribution experiments with human bladder tumor xenografts in athymic nude mice using radiolabeled monoclonal antibody 425 and an isotype matched control antibody demonstrated specific tumor localization at five and seven days following antibody injection. Successful imaging of a human bladder tumor xenograft was achieved five days post antibody injection. These data confirm that epidermal growth factor receptor expression correlates with bladder cancer stage and suggests that epidermal growth factor receptor may serve as a target antigen for radioimmunoscintigraphy.

Animals↗
PubMed1991

Inpatients with AIDS and AIDS-related complex: economic inpact on hospitals in North Carolina.

To determine the economic impact of acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC) cases on North Carolina hospitals, we collected inpatient data from all North Carolina hospitals on charges and number of patients discharged with these diagnoses. More than 97% of the state's hospitals responded to the survey for the study year (1987-1988). There were 540 AIDS/ARC discharges from 58 North Carolina general hospitals and 125 AIDS/ARC discharges from 13 other types of hospitals, for a statewide total of 665 patients. The total general hospital charges for AIDS/ARC inpatients in North Carolina were approximately $7.7 million per year, and almost $2 million of these charges were uncompensated by any insurance. The greatest burden of cost for this care was borne disproportionately by 15 of the 58 general hospitals, accounting for 82% of the discharges.

AIDS-Related Complex↗
PubMed1991

What children see affects how they read.

Children of mixed abilities were given three single-word lists to read, matched for linguistic complexity. The visual component of the task was made harder by reducing the print size with each new list. The reading errors made by children who did and who did not have a visual impairment were compared. The visually impaired children's pattern of reading errors changed as their vision was stressed by the reduction in print size; their errors became non-words (neologisms). This finding suggests a link between the efficiency of visual processing and the accuracy of reading of these children.

Aptitude↗
PubMed1991

Hydrostatic pressure influences histone mRNA.

Exposure of HeLa S3 cells to high hydrostatic pressure (6.89 x 10(3) to 6.89 x 10(4) kPa: 1000 to 10,000 lbfin-2) reduced core and H1 histone mRNA levels as determined by hybridization to specific histone DNA probes. At 4.14 x 10(4) kPa for 10 min core histone and H1 histone mRNA levels were reduced 32-38% and 56%, respectively. At 30 min postdecompression core mRNA levels returned to atmospheric control levels while H1 histone mRNA levels continued to be suppressed. Levels of macromolecular synthesis were monitored under hydrostatic pressure with radioactive precursors of RNA, DNA and protein. Macromolecular synthesis was shown to be suppressed in a dose-dependent manner with increasing magnitude and duration of pressure. To determine the influence of pressure on histone mRNA stability, actinomycin D (10 micrograms ml-1) was used to block RNA synthesis. Relative amounts of H4 and H1 mRNA were determined at atmospheric pressure and following treatment with actinomycin D (10 micrograms ml-1), pressure (4.14 x 10(4) kPa) and a combination of pressure and actinomycin D. This study shows that a synthesis component and a stability component are involved in the pressure-induced reduction of core histone mRNA. At 4.14 x 10(4) kPa for 15 min, there was a 42% reduction in core histone mRNA of which approximately one third was due a suppression of transcription and two thirds to a loss of mRNA stability. The pressure-induced reduction in histone mRNA is attributed to the instability of endogenous histone mRNA and a reduction in transcription/processing of new histone mRNA.

HeLa Cells↗