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Biomedical subjects

M Jacobs

Publications and source records attributed to M Jacobs.

At least 55 records · Page 3Linked to original sources
PubMed1998

Potential interaction of troglitazone and cyclosporine.

BACKGROUND: Troglitazone (Rezulin) is a promising new oral hypoglycemic agent recently approved by the Federal Drug Administration for use in type II diabetes mellitus. Although troglitazone is not metabolized by the cytochrome p450 3A isozyme family, it is a potential inducer of this system. Other medications, e.g., rifampin and phenobarbital, which also induce p450 3A activity, have been reported to significantly decrease cyclosporine (CsA) concentrations. METHODS: We report a case of a stable renal transplant patient who had a decrease in CsA concentration after beginning troglitazone and who subsequently developed an acute rejection episode. We then reviewed all stable renal patients begun on troglitazone over the previous 6 months. RESULTS: The seven transplant patients who had been started on troglitazone therapy experienced a statistically and clinically significant decrease in CsA 12-hr trough levels immediately after the institution of troglitazone therapy. CONCLUSION: A potential interaction exists between troglitazone and CsA. Transplant patients on CsA who receive troglitazone therapy should be monitored closely.

Acute Disease↗
PubMed1998

3-Nitrotyrosine in the proteins of human plasma determined by an ELISA method.

The modification of tyrosine residues in proteins to 3-nitrotyrosine by peroxynitrite or other potential nitrating agents has been detected in biological systems that are subject to oxidative stress. A convenient semi-quantitative method has been developed to assay nitrated proteins in biological fluids and homogenates using a competitive ELISA developed in our laboratory. This assay selectivity detected 3-nitro-l-tyrosine residues in a variety of peroxynitrite-treated proteins (BSA, human serum albumin (HSA), alpha1-antiprotease inhibitor, pepsinogen and fibrinogen) and also in a nitrated peptide, but had a low affinity for free 3-nitro-L-tyrosine and 3-chloro-L-tyrosine. The IC50 values for the inhibition of antibody binding by different nitrated proteins were in the range 5-100 nM, suggesting that the antibody discriminated between nitrotyrosine residues in different environments. The presence of nitrotyrosine in plasma proteins was detected by Western blot analysis and quantified by the ELISA. A concentration of 0. 12+/-0.01 microM nitro-BSA equivalents was measured in the proteins of normal plasma which was increased in peroxynitrite-treated plasma and was elevated in inflammatory conditions. HSA and low-density lipoprotein (LDL) isolated from plasma contained 0.085+/-0.04 and 0. 03+/-0.006 nmol nitro-BSA equivalents/mg protein, respectively. Comparison of the level of nitration in peroxynitrite-treated HSA and LDL in the presence and absence of plasma indicates that nitration and presumably oxidation is inhibited by plasma antioxidants. The presence of nitrotyrosine in LDL is consistent with previous reports implicating peroxynitrite in the oxidative modification of lipoproteins and the presence of a low concentration of oxidized LDL in the blood.

Adult↗
PubMed1998

Molecular cloning and expression of a cDNA sequence encoding histidinol phosphate aminotransferase from Nicotiana tabacum.

A Nicotiana tabacum cDNA sequence encoding histidinol phosphate aminotransferase (HPA) was isolated by functional complementation of an Escherichia coli histidine auxotroph (UTH780). The enzymatic assay has confirmed that the isolated cDNA encodes a functional HPA protein. Amino acid sequence alignment of the HPA protein from N. tabacum, Saccharomyces cerevisiae and E. coli revealed that, despite the low degree of identity, some residues were found to be highly conserved. The predicted protein contains a transit peptide sequence at the amino-terminal end, suggesting a chloroplastic localization of the HPA enzyme. Western blot analysis demonstrated that the deduced HPA protein and the mature HPA protein have an apparent molecular mass of about 45 kDa and 40 kDa respectively. Gene copy number estimation by Southern analysis indicates the presence of at least two genes per haploid genome coding for this protein in Nicotiana sp. From northern analysis results, the gene seems to be highly expressed in green tissues and the detected transcript showed a single band of expected molecular size.

Amino Acid Sequence↗
PubMed1998

A novel human type II cytokeratin, K6hf, specifically expressed in the companion layer of the hair follicle.

In an attempt to identify new members of the human type II hair keratin family by means of 3'- and 5'-RACE methods and cDNA from anagen hair follicles, we detected a sequence that encoded a hitherto unknown type II cytokeratin. The novel cytokeratin comprises 251 amino acids and exhibits the highest sequence homology with K5. Comparative one- and two-dimensional western blots of keratins from anagen hair bulbs, containing or not containing the outer and inner root sheaths (ORS/IRS), and from footsole epidermis with an antibody against the new cytokeratin, revealed its comigration with K6 and its expression in the ORS/IRS complex. We have therefore named the new cytokeratin K6hf, to distinguish it from the various K6 isoforms and to indicate its expression in the hair follicle. Both in situ hybridization with a K6hf-specific cRNA probe and indirect immunofluorescence with the K6hf antibody showed that K6hf is exclusively expressed in the so-called "companion layer" of the hair follicle, a single layered band of flat and vertically oriented cells between the cuboidal ORS cells and the IRS that stretches from the lowermost bulb region to the isthmus of the follicle. Concomitant K17 and K16 expression studies showed that besides suprabasal ORS cells, these cytokeratins are sequentially expressed subsequent to K6hf in companion cells above the hair bulb. Our study confirms the view of a vertically oriented companion layer differentiation. The clearly delayed K17 and K16 expression relative to that of K6hf in companion cells most probably excludes these keratins as possible type I partners of K6hf and suggests the existence of a still unknown type I partner of its own. Thus, not only morphologically but also biochemically, the companion layer is different from the ORS and can therefore be regarded as an independent histologic compartment of the hair follicle.

Amino Acid Sequence↗
PubMed1998

Isolation of the ornithine-delta-aminotransferase cDNA and effect of salt stress on its expression in Arabidopsis thaliana.

To evaluate the relative importance of ornithine (Orn) as a precursor in proline (Pro) synthesis, we isolated and sequenced a cDNA encoding the Orn-delta-aminotransferase (delta-OAT) from Arabidopsis thaliana. The deduced amino acid sequence showed high homology with bacterial, yeast, mammalian, and plant sequences, and the N-terminal residues exhibited several common features with a mitochondrial transit peptide. Our results show that under both salt stress and normal conditions, delta-OAT activity and mRNA in young plantlets are slightly higher than in older plants. This appears to be related to the necessity to dispose of an easy recycling product, glutamate. Analysis of the expression of the gene revealed a close association with salt stress and Pro production. In young plantlets, free Pro content, Delta1-pyrroline-5-carboxylate synthase mRNA, delta-OAT activity, and delta-OAT mRNA were all increased by salt-stress treatment. These results suggest that for A. thaliana, the Orn pathway, together with the glutamate pathway, plays an important role in Pro accumulation during osmotic stress. Conversely, in 4-week-old A. thaliana plants, although free Pro level also increased under salt-stress conditions, the delta-OAT activity appeared to be unchanged and delta-OAT mRNA was not detectable. Delta1-pyrroline-5-carboxylate synthase mRNA was still induced at a similar level. Therefore, for the adult plants the free Pro increase seemed to be due to the activity of the enzymes of the glutamate pathway.

Amino Acid Sequence↗
PubMed1998

Criteria for evaluating alternative MEDLINE search engines.

With so many options available for searching MEDLINE on the World Wide Web or as a component of an online service, evaluation criteria are suggested as a means of assisting librarians in determining the positive and negative aspects of alternative MEDLINE sites. A set of searches was utilized to systematically compare MEDLINE sites. Sites evaluated included Avicenna, America Online, HealthGate, PubMed, Medscape, and Physicians' Online. Some features used to evaluate these sites were: default fields; operators (default); access to MeSH; subheadings; stop words protected in MeSH; truncation; and stemming. This article will describe the group process used to arrive at the evaluation criteria, as well as some general conclusions which will help librarians in directing their users to a particular MEDLINE site.

Abstracting and Indexing↗
PubMed1998

Continence nurses: a survey of who they are and what they do.

This survey is the first report on the characteristics, functions, and barriers to practice reported by continence care nurses in the United States. The data obtained provide valuable information regarding a new subspecialization in nursing.

Adolescent↗
PubMed1997

Relapse and rehospitalization during maintenance treatment of schizophrenia. The effects of dose reduction and family treatment.

BACKGROUND: Previous studies have examined dose reduction and family treatment in schizophrenia, but none has examined their interaction. This study assessed the impact of dose reduction of antipsychotic medication and family treatment on relapse and rehospitalization during maintenance treatment. METHODS: Subjects were 313 male and female outpatients at 5 centers with a DSM-III-R diagnosis of schizophrenia or schizoaffective disorder. In a 3 x 2 design, subjects were randomized to 1 of 3 medication strategies using fluphenazine decanoate under double-blind conditions: continuous moderate dose (standard) (12.5-50 mg every 2 weeks); continuous low dose (2.5-10 mg every 2 weeks); or targeted, early intervention (fluphenazine only when symptomatic). Subjects also were randomized to 1 of 2 family treatment strategies (supportive or applied). Supportive family management involved monthly group meetings. The more intensive applied family management involved monthly group meetings and home visits where communication and problem-solving skills were taught. Patients and families were treated and assessed for 2 years. RESULTS: Both continuous low-dose and targeted treatment increased use of rescue medication and relapse; only targeted treatment increased rehospitalization. This pattern was consistent across both family treatments; there were no differences between family treatments. CONCLUSIONS: These findings reaffirm the value of antipsychotic medication in preventing relapse and rehospitalization. The absence of family treatment differences may be because both conditions engaged families.

Adolescent↗
PubMed1997

Screening for Down syndrome using urine hCG free beta-subunit in the second trimester of pregnancy.

Human chorionic gonadotropin (hCG) free beta-subunit levels were determined in 709 control and 13 Down syndrome urine samples from the second trimester of pregnancy. Results were normalized to urine creatinine concentration and converted to multiples of the unaffected pregnancy medium (MOM). The concentration of free beta-subunit in Down syndrome cases was 3.9 MOM. Seven of 13 Down syndrome pregnancies (54 per cent) had free beta-subunit levels at or above the 95th centile of unaffected pregnancies. Urine free beta-subunit may potentially be useful as a screening test for Down syndrome.

Adult↗
PubMed1997

Is laparoscopic surgery applicable to complicated colonic diverticular disease?

BACKGROUND: Expanding upon our experience with laparoscopic surgery for colonic benign and malignant processes and for bowel obstruction, we have reviewed our experience with minimal access laparoscopic surgery for complicated diverticular disease. We propose an approach of surgical care incorporating diagnostic laparoscopy in those not responding to medical therapy alone. METHODS: Our study includes data from two different surgical teams working in separate hospital-and-patient environments. Our theory that laparoscopy could be widely applicable to this complex disease process is borne out by experience in both locations. One hundred forty-eight patients were managed by laparoscopic or laparoscopically assisted methods with 18 patients requiring drainage only without resection. RESULTS: Our management of 148 of 164 patients (90%) by laparoscopic approach was successful, with a very acceptable morbidity of 5% in the elective cases and decreased ileus (20% of open vs 7% laparoscopic) in acute complicated cases. Elective resections required hospitalization of 4-5 days, demonstrating the benefits of incorporating laparoscopy in the care of these cases, particularly when compared to standard open procedures requiring 8 days' hospitalization. CONCLUSIONS: We believe complications of diverticular disease including abscess, perforation, fistula, and bleeding can potentially be managed in this way by minimal access procedures, decreasing postoperative wound problems, decreasing length of hospitalization and overall morbidity, and improving patient care.

Adult↗