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Biomedical subjects

D Busch

Publications and source records attributed to D Busch.

At least 19 recordsLinked to original sources
PubMed1999

Carbon source-dependent regulation of cell growth by murine protein kinase C epsilon expression in Saccharomyces cerevisiae.

Protein kinase C is known to play a role in cell cycle regulation in both lower and higher eucaryotic cells. Since mutations in yeast proteins involved in cell cycle regulation can often be rescued by the mammalian homolog and since significant conservation exists between PKC-signalling pathways in yeast and mammalian cells, cell cycle regulation by mammalian PKC isoforms may be effectively studied in a simpler genetically-accessible model system such as Saccharomyces cerevisiae. With this objective in mind, we transfected S. cerevisiae cells with a plasmid (pYECepsilon) coding for the expression of murine protein kinase C epsilon (PKCepsilon) under the control of a galactose-inducible promoter. Unlike mock-transfected cells, yeast cells transformed with pYECepsilon expressed, in a galactose-dependent manner, an 89 kDa protein that was recognized by a human PKCepsilon antibody. Extracts from these pYECepsilon-transfected cells could phosphorylate a PKCepsilon substrate peptide in a phospholipid/phorbol ester-dependent manner. Moreover, this catalytic activity could be inhibited by a fusion protein in which the regulatory domain of murine PKCepsilon was fused in frame with GST (GST-Repsilon), further confirming the successful expression of murine PKCepsilon. Induction of PKCepsilon expression by galactose in cells transformed with pYECepsilon increased Ca++ uptake by the cells approximately 5-fold and resulted in a dramatic inhibition of cell growth in glycerol. However, when glucose was used as the carbon source, PKCepsilon expression had no effect on cell growth. This was in contrast to what was observed upon bovine PKCalpha or PKCbeta-I expression in yeast, where expression of these PKC isoforms strongly and moderately inhibited growth in glucose, respectively. Visualization of the cells by phase contrast microscopy indicated that murine PKCepsilon expression in the presence of glycerol resulted in a significant increase in the number of yeast cells exhibiting very small buds. Since overall growth of the cells was dramatically decreased, the data suggests that PKCepsilon expression potently inhibits the progression of yeast cells through the cell cycle after the initiation of budding. In addition, a small amount of the PKCepsilon-expressing yeast cells (1-2%) exhibited gross alterations in cell morphology and defects in both chromosome segregation and septum formation. This suggests that for those cells which do complete DNA synthesis, murine PKCepsilon expression may nevertheless inhibit yeast cell growth by retarding and/or imparing cell division. Taken together, the data suggests murine PKCepsilon expression potently reduces the growth of yeast cells in a carbon source-dependent fashion by affecting progression through multiple points within the cell cycle. This murine PKCepsilon-expressing yeast strain may serve as a very useful tool in the elucidation of mechanism(s) by which external environmental signals (possibly through specific PKC isoforms) regulate cell cycle progression in both yeast and mammalian cells.

Animals↗
PubMed1997

UV-sensitive rodent mutant cell lines of complementation groups 6 and 8 differ phenotypically from their human counterparts.

Rodent UV-sensitive mutant cell lines of complementation groups 6 and 8 are the genetic counterparts of human Cockayne syndrome CS-B and CS-A, respectively. The original mutant in this group, UV61, was described as defective in cyclobutane pyrimidine dimer removal after high doses of UV. We have examined the responses of several cell lines from group 6 to low doses of UV irradiation, and find that these mutants have wild-type capacity for DNA repair as indicated by incision, cyclobutane pyrimidine dimer, and (6-4) photoproduct removal. ERCC6, the product of the gene defective in CS-B and group 6 mutants, is implicated in the regulation of repair of actively transcribed genes in Cockayne syndrome; however, this protein clearly is not required for the processing of low levels of damage in CHO cells, which occurs remarkably efficiently, 40-50% of dimers being removed in both wild-type and group 6 mutants in 5 hours following 0.1 Jm(-2) of UV. The group 8 mutant cell line US31, on the other hand, is very deficient in repair of UV damage, showing a more extreme phenotype than is seen in the corresponding human syndrome CS-A. In both complementation groups, expression of mutations in a gene involved in regulation of DNA repair takes very different forms in human and rodent cells.

Animals↗
PubMed1996

Diarrhea in young children associated with Escherichia coli non-O157 organisms that produce Shiga-like toxin.

OBJECTIVE: To assess the clinical manifestations and incidence of infection associated with Shiga-like toxin-producing Escherichia coli (SLTEC). STUDY DESIGN: Children with diarrhea within a defined geographic area during a 12-month period were examined for the presence of SLTEC in their stools by polymerase chain reaction with the use of primers that were complementary to sequences of Shiga-like toxins types I and II and to other virulence factors. RESULTS: There were 13 SLTEC infections among 468 children with diarrhea. Besides Shiga-like toxin sequences, the virulence genes eae and EHEC-hly were found in 10 isolates; these isolates were categorized as enterohemorrhagic E. coli (EHEC). Only 2 of 13 isolates were of the O157 strain. All reported cases occurred in summer (June through September) with the exception of one case in April. The infections were sporadic, and the infected children lived in rural and urban areas. Three infections in children with disabilities were hospital acquired. The majority of children had watery diarrhea, two had bloody diarrhea, and one had mild hemolytic-uremic syndrome. The overall incidence of SLTEC infection was 12.5 hospitalized children per 100,000 children less than 16 years of age. CONCLUSIONS: The most frequent clinical manifestation of SLTEC infection was watery diarrhea indistinguishable from other forms of infectious diarrhea. The shift from the O157 strain toward non-O157 SLTEC strains associated with diarrhea, also observed in German patients with hemolytic-uremic syndrome, points to a change in the epidemiologic features of SLTEC-associated disease. Testing for non-O157 SLTEC should be considered in children with diarrhea without a recognized cause.

Bacterial Toxins↗
PubMed1995

Population differences in ganciclovir clearance as determined by nonlinear mixed-effects modelling.

We examined the pharmacokinetics of ganciclovir in different populations of cytomegalovirus (CMV)-infected patients through the use of nonlinear mixed-effects modelling. As expected, patient weight and estimated creatinine clearance were shown to be important covariates in the serum ganciclovir clearance. Unexpectedly, major differences in ganciclovir clearance between different populations of patients were found. Human immunodeficiency virus (HIV)-infected patients with CMV retinitis cleared ganciclovir 41% faster than HIV-infected patients only shedding CMV into the urine. Solid-organ transplant patients had a serum clearance one-fourth that of HIV-infected patients, even with correction for creatinine clearance. These findings require prospective validation and may have important implications for ganciclovir dosing in different populations of CMV-infected patients.

AIDS-Related Opportunistic Infections↗
PubMed1994

Genetic susceptibility to radiation and chemotherapy injury: diagnosis and management.

Over 5% of the cancer patient population may be radiation sensitive due to genetics, and the sensitive patients may be greatly overrepresented among patients with cancer therapy complications. These individuals include not only rare ataxia telangiectasia (AT) homozygotes with up to three-fold normal radiation sensitivity, but also far more numerous patients with slight radiosensitivity conjectured to be carriers of AT or to have another inherited mutagen sensitivity. Procedures may eventually be used to reliably determine patient tolerance for radiation and antineoplastic agents before initiation or completion of therapy, to have the therapy approach but not exceed the radiation tolerance of the individual patient's irradiated normal tissue. Such procedures could include study of patient's cultured normal cells (e.g., fibroblasts, marrow cells, or lymphocytes) in much the same way that patients' cultured tumor cells may eventually be widely used in the human tumor stem cell assay to predict which course of radiotherapy or chemotherapy should be most useful for treating a cancer. Studies with the normal cells could include cytotoxicity assays, serially determined accumulated genetic damage over the course of therapy, or Southern blot analysis to identify carriers of DNA repair mutations. Such studies could permit more aggressive radiotherapy of most patients due to the noninclusion of a sensitive subpopulation of patients, with less radiotherapy of the relatively few radiation sensitive patients. The patient's tumor cells should have inherited any radiation (or chemotherapy) sensitivity mutations present in the patient's normal cells, so reducing the radiotherapy dose to compensate for the more radiosensitive patients' sensitivity will not necessarily result in undertreatment of the tumor.

Antineoplastic Agents↗
PubMed1994

Complementation group assignments of moderately UV-sensitive CHO mutants isolated by large-scale screening (FAECB).

The complementation group (CG) assignment is presented for 74 moderately sensitive (approximately 2-4x sensitivity of parental line based on ratio of D10s) UV-sensitive mutants of Chinese hamster ovary (CHO) cells from the Facility for Automated Experiments in Cell Biology (FAECB) collection. The distribution of mutants within the first five rodent UV CGs was similar to that of previously reported highly sensitive (> 4x wild-type UV sensitivity) mutants from this collection. This analysis nearly completes the identification of this large collection of over 200 mutant lines isolated after screening an estimated 3 million total colonies of mutagenized CHO cells from approximately 20 mutant hunts with up to about 400,000 colonies screened. Only eight lines with less than about 2x parental line UV sensitivity remain unassigned. One CG of UV mutants (CG6), which now has five identified representatives in the collection, has only been found among moderately UV-sensitive CHO cells. Mutant UV40, a mitomycin C (MMC)- and X-ray-sensitive line with moderate UV cross-sensitivity, is not in CGs 1-6 and apparently is not a nucleotide excision repair mutant. Also identified were new alleles of CG1 and CG4 mutants with profoundly deficient unscheduled DNA synthesis and moderate UV sensitivity but low sensitivity to MMC. The first CG5 mutant derived from MMC-sensitive MC5 cells has been identified as the second CG5 mutant in the collection. No representatives of rodent CGs 7-11 were found, suggesting that AA8 cells have a chromosomal makeup that precludes easy isolation of mutants in these CGs.

Animals↗
PubMed1993

[Generalized nocardiosis with meningoencephalitis in a nonimmunosuppressed female patient].

Four weeks after an attack of pneumonia of unknown aetiology a 40-year-old woman was hospitalized because of a nonpurulent, predominantly basal meningoencephalitis and infratentorial abscesses. She had dysarthria, mild right-sided motor hemiparesis and central paresis affecting the 7th cranial nerve. An area of fluctuating resistance, about 3 cm in diameter, was noticed over the left thigh. Serology indicated inflammatory disease, but there was no immunodeficiency. The CSF showed lymphocytic pleocytosis with mild protein increase but no evidence of infective agent. As tubercular meningitis was suspected she was treated with rifampicin (300 mg i.v. twice daily), isoniazid (300 mg i.v. once daily), streptomycin (800 mg i.m. once daily), cefotaxime (2.0 g i.v. three times daily), fluconazole (200 mg i.v. once daily) and dexamethasone (16-8-8 mg i.v.). She suddenly died two days after admission, probably as the result of central regulatory failure. Generalized nocardiosis involving lung, subcutaneous tissue and brain was revealed at autopsy. Although nocardiosis occurs predominantly in patients under immunosuppression, this infection should be considered in the differential diagnosis of treatment-resistant pneumonia and meningoencephalitis without obvious predisposition.

Adult↗
PubMed1990

Aerosolized pentamidine for prophylaxis against Pneumocystis carinii pneumonia. The San Francisco community prophylaxis trial.

BACKGROUND AND METHODS: Pneumocystis carinii pneumonia (PCP) is the most frequent life-threatening opportunistic infection associated with human immunodeficiency virus (HIV) infection. To assess the possible value of aerosolized-pentamidine prophylaxis in different doses, a controlled clinical trial was begun in 1987 with 408 subjects at 12 treatment centers. The participants were randomly assigned to receive 30 mg of pentamidine every two weeks, 150 mg every two weeks, or 300 mg every four weeks. RESULTS: Eighteen months after randomization, the subjects in the 300-mg arm had had 8 confirmed episodes of PCP while receiving treatment, as compared with 22 in the 30-mg arm (P = 0.0008). The 150-mg arm had intermediate results but ones not significantly different from those of the 300-mg arm. Participants with previous episodes of PCP and CD4-cell counts less than 200 per cubic millimeter were at the highest risk for PCP. CONCLUSIONS: Aerosolized pentamidine was effective for prophylaxis against PCP in patients infected with HIV, according to the dose and schedule of administration. It and zidovudine were well tolerated together and had independent prophylactic benefits.

Adult↗
PubMed1989

[Follow-up of local lytic therapy of pulmonary emboli using DSA].

The series consisted of 30 patients with pulmonary emboli diagnosed by DSA. In 18 patients repeat DSA was performed using the central catheter which had been employed for the lytic therapy immediately after the end of treatment. Therapy was carried out from two to 14 days. Bleeding was observed in four of the patients. The final DSA showed complete recanalisation in five patients, partial recanalisation in 11 patients and no angiographic improvement in two.

Adult↗
PubMed1989

[Computed tomography and magnetic resonance tomography of the lower leg in chronic venous insufficiency].

Sixty-two lower limbs in 29 women and six men with chronic venous insufficiency (CVI) of grade II and III were examined by CT and eight of these additionally with MRI. The changes were compared with the findings in 21 patients of similar age, but without venous abnormalities. The most important findings were subcutaneous fibrosis with or without calcification, nonspecific infiltration of the extrafascial spaces and degeneration of the Achilles' tendon. The simultaneous occurrence of these changes can be regarded as typical of advanced CVI. CT was somewhat superior to MRI; its use can be justified as part of posttherapeutic follow-up and for special problems.

Adult↗
PubMed1989

Summary of complementation groups of UV-sensitive CHO cell mutants isolated by large-scale screening.

A summary is given for the lineage and complementation group assignments of 153 UV-sensitive mutants of the CHO AA8 cell line. The distribution of mutants among six complementation groups was highly non-random, with the great majority of the isolates belonging to groups 1 and 2. This asymmetry is consistent with the known hemizygosity of these two linked loci in CHO cells. The relative numbers of mutants induced in group 2 was found to depend greatly on the type of mutagen used. Mutagenesis with UV radiation, ethyl methanesulfonate (EMS), N-methyl-N'-nitro-N-nitrosoguanidine and 7-bromomethylbenz[a]anthracene produced high frequencies of group 2 mutants. In contrast, ICR170 and ICR191, which are thought to produce mostly frameshift mutations, yielded very few mutants in group 2. These results are of particular importance in light of the recent finding that the human ERCC2 gene, which corrects group 2 mutants, has very strong homology with the yeast gene RAD3. RAD3 is an essential gene for viability in yeast, and the low recovery of group 2 mutants using the frameshift agents strongly suggests that frameshift mutations tend to be lethal in the hamster ERCC2 locus. Several mutagen-sensitive double mutants were isolated in two-step selections from EMS-, mitomycin C- or UV-sensitive parental cells, including the line UVU1, the first mammalian line with two mutations that affect UV sensitivity. The first mutation inactivated excision repair, and the second mutation appears to have affected some other recovery process. UVU1 should be useful for studying recovery processes that are separate from nucleotide excision repair.

Animals↗
PubMed1989

[Does Hepavis have value in the therapy of fatty liver caused by alcohol poisoning?].

During the therapy of fatty liver (resp. fatty liver hepatitis) the additional application of Hepavis besides the prohibition of alcohol does not have any advantages in comparison to an additional application of a placebo. So the significant decrease of the fat content of the liver under those circumstances seems to be only the consequence of lacking alcohol consume, but not a specific effect of Hepavis. Consequently the treatment of alcoholtoxic fatty liver can be no other than to avoid alcohol, one of the most important causes of illness nowadays.

Adult↗
PubMed1989

[Computerized tomography studies of the lower legs of patients with chronic venous insufficiency and arthrogenic venous stasis syndrome].

Transverse computed tomography of the lower legs in patients with chronic venous insufficiency reveals changes in the extravasal connective tissue. In the subcutaneous fat there is fibrosis - sometimes with ossification - that may extend to the periachilloregion and then embeds the Achilles tendon. The Achilles tendon has a reduced cross-section and reduced density with circumscribed, hypodense areas that are a sign of degeneration. In the muscles, areas of atrophy with lipomatous degeneration can be found as well. In the bones there are signs of increased osteoporosis; the periosteum shows osseous proliferation. The extent of these changes correlates with the degree of venous insufficiency and is most often seen in patients with the arthrogenic stasis syndrome.

Achilles Tendon↗
PubMed1987

Risk of AIDS-related virus (human immunodeficiency virus) transmission through apheresis procedures.

Since exposure to blood products occurs on a daily basis during hemapheresis, the acquired immunodeficiency syndrome (AIDS) epidemic has a serious impact both for patients undergoing apheresis procedures as well as for health professionals working in the field. We studied serum samples from 110 patients who underwent therapeutic plasmapheresis for a variety of diseases not related to AIDS for the presence of antibodies to human immunodeficiency virus (HIV). Exchange fluids used in the majority of the patients were plasma protein fraction and 5% human albumin. Four patients received only fresh-frozen plasma. Fifty-five patients also received IV gammaglobulin. The follow-up period exceeded 24 months. All patients who did not belong to any known high-risk group for AIDS were negative for HIV antibodies prior to treatment and remained negative at last follow-up. Seven patients were homosexual men. All seven were seropositive prior to plasmapheresis and remained so throughout the treatment period. Seven health professional working in a busy haemapheresis unit were followed for 2 1/2 years. All remain HIV seronegative with normal immune function. These data indicate that transmission of HIV is unlikely through haemapheresis procedures.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Growth hormone and prolactin response to apomorphine in schizophrenia and the major affective disorders. Relation to duration of illness and depressive symptoms.

The responses of serum prolactin (PRL) and growth hormone (GH) to the dopamine agonist apomorphine hydrochloride (0.75 mg subcutaneously) were studied in a large group of unmedicated hospitalized patients with functional psychoses. There were no differences in the GH response in various diagnostic groups. The PRL response was greater in patients with affective disorders. The GH response was inversely related to total duration of illness in the entire sample of patients, but this correlation was independent of age effect only in the group of patients with major depression. In schizophrenics, the effect of the two factors, age and duration of the illness, could not be separated. The apomorphine-induced GH response was significantly correlated with psychosis ratings and negative symptom scale scores. The apomorphine-induced PRL suppression correlated significantly with various measures of depression across diagnostic groups.

Adolescent↗
PubMed1983

Serum prolactin response to chlorpromazine and psychopathology in schizophrenics: implications for the dopamine hypothesis.

The prolactin (PRL) response to 12.5 and 25 mg of chlorpromazine (CPZ) was studied in unmedicated schizophrenic patients and normal control subjects. Both doses produced significant increases in serum PRL levels compared to saline, but the response to 25 mg CPZ was significantly greater than that to 12.5 mg. The PRL response to the 12.5 mg dose only was significantly correlated with baseline PRL levels for both males and females, suggesting that endogenous dopamine release from tuberoinfundibular neurons has a much greater effect upon the PRL response to the 12.5 mg dose of CPZ than to the 25 mg dose. Both doses of CPZ tended to show lower PRL responses in the schizophrenic females. The PRL response to the 25 mg dose was negatively correlated with ratings of severity of delusions at the time of study. The PRL response to 25 mg correlated highly with the morning serum PRL levels following treatment with CPZ 100 mg and 200 mg orally b.i.d. for 1 week at each dose. The PRL response to both doses did not predict clinical response at the end of 2 weeks of treatment with fixed dosages of CPZ. Serum PRL levels during treatment with CPZ 200 mg b.i.d. were significantly negatively correlated with ratings of hallucinations. The negative correlations between severity of delusions and hallucinations and various PRL measures suggest that increased dopaminergic activity in the tuberoinfundibular hypothalamic-pituitary axis may be associated with increased activity of subcortical and cortical dopaminergic systems.

Adult↗