Search PubMed⌕ Search

Biomedical subjects

L Hall

Publications and source records attributed to L Hall.

At least 91 records · Page 5Linked to original sources
PubMed1995

Cytokeratin expression in human respiratory epithelium of nasal polyps and turbinates.

The cytokertatins in respiratory epithelial cells (REC) of human nasal polyps and turbinates were analyzed by immunohistochemistry. Cytokeratin 19 (CK19) was present in all REC, CK5 and 14 were expressed primarily in basal cells, and CK7, 8, and 18 were found in suprabasal cells. Differences in cytoplasmic locations were also apparent among the individual cytokeratins. CK13 was not detected in any REC of these tissues. The results indicate the profile of cytokeratins in REC of human nasal polyps and turbinates is essentially identical to that of REC in the more distal respiratory tract.

Antibodies, Monoclonal↗
PubMed1995

Sequence analysis of two chromosomally mediated inducible beta-lactamases from Aeromonas sobria, strain 163a, one a class D penicillinase, the other an AmpC cephalosporinase.

Two beta-lactamase genes from Aeromonas sobria, strain 163a, have been cloned and sequenced, one encoding a typical class C cephalosporinase, designated CepS, the other a class D penicillinase, designated AmpS. CepS is predicted to be a mature protein of 38 kDa with a pI value of 7.0. The amino acid sequence of CepS is most similar to that of AmpC from Pseudomonas aeruginosa (54.7%). AmpS is predicted to be a mature protein of 27 kDa with a pI value of 7.9 that mostly closely resembles BLAD from Klebsiella pneumoniae (42.2%), and OXA-1 from Escherichia coli (36.6%), beta-lactamases that are encoded by genes carried on multiresistant transposons. AmpS differs significantly from the other class D beta-lactamases in that it hydrolyses cloxacillin poorly and is inducible. Both genes exhibit a high overall GC content and possess a high NNC and NNG codon preference, similar to that of genes from Pseudomonas spp.

Aeromonas↗
PubMed1995

Efficacy of D0870 compared with those of itraconazole and amphotericin B in two murine models of invasive aspergillosis.

D0870 is a novel azole antifungal compound. It was compared with conventional amphotericin B and itraconazole therapy in two murine models of invasive aspergillosis, one a systemic nonimmunocompromised mouse model and the other a temporarily neutropenic mouse respiratory model. D0870 was given orally and achieved measurable concentrations in serum approximately proportional to the daily dose with accumulation over time if it was given twice daily. Amphotericin B at 3.3 mg/kg of body weight was given intraperitoneally for four to six doses, and itraconazole was given orally in a cyclodextrin suspension at 5 to 50 mg/kg daily or twice daily (BID). The duration of therapy varied from 7 to 14 days. In the nonimmunocompromised mouse model, D0870 at 25 mg/kg BID was slightly inferior to amphotericin B and itraconazole with regard to mortality, with a median survival of 20 days for the three groups (P = 0.03 compared with amphotericin B). However, D0870 at 25 mg/kg BID was inferior to amphotericin B (but not itraconazole) with respect to renal culture (P = 0.01) and brain culture (P = 0.0001) results. Only amphotericin B was statistically superior to controls with regard to mortality. In the neutropenic mouse respiratory model, D0870 at 50 mg/kg/day was superior to amphotericin B, itraconazole, and controls with regard to mortality. D0870 at both 25 and 50 mg/kg/day was statistically superior to controls with regard to lung culture results (P = 0.004 to 0.04). A second experiment with a higher inoculum showed that no drug regimen was effective in that model. In all models low doses and concentrations of D0870 in serum were ineffective. D0870 has some efficacy for the treatment of invasive aspergillosis when it is given at modest doses.

Amphotericin B↗
PubMed1995

Exhaled nitric oxide in isolated pig lungs.

Endothelium-derived nitric oxide (NO) is an important regulator of vascular resistance. Low concentrations of NO have been recorded in the exhaled breath of spontaneously breathing animals and humans. To determine whether NO synthesis in the lung contributes to the NO measured in the breath, we measured the concentration of NO in the exhaled air of isolated perfused and ventilated porcine lungs by using a chemiluminescence method. With NO-free normoxic ventilation (21% O2-5% CO2-74% N2) of eight porcine lungs perfused with a Krebs-dextran and albumin perfusate, baseline exhaled NO was 5.8 +/- 1.8 parts per billion (ppb) and pulmonary vascular resistance (PVR) was 8.9 +/- 1.8 mmHg.l-1.min. Hypoxic ventilation (5% O2-5% CO2-90% N2) caused a fall in NO to 3.6 +/- 1.8 ppb and a rise in PVR to 13.6 +/- 3.6 mmHg.l-1.min. Vasoconstriction with the thromboxane analogue U-46619 (10(-9) M) raised PVR to 31.7 +/- 6.8 mmHg.l-1.min but did not decrease NO levels from baseline. Subsequent addition of acetylcholine (10(-6)M) lowered PVR to 22.1 +/- 4.5 mmHg.l-1.min and increased exhaled NO to 7.0 +/- 2.0 ppb. Addition of a NO synthase inhibitor, NG-nitro-L-arginine methyl ester (10(-5) M), to four lungs caused a rise in PVR to 43.0 +/- 7.0 mmHg.l-1.min and a decrease in NO to 1.5 +/- 1.0 ppb. Addition of autologous blood to the perfusate of four lungs caused no change in PVR from baseline but decreased exhaled NO to 2.7 +/- 0.5 ppb.(ABSTRACT TRUNCATED AT 250 WORDS)

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1995

Cloning and expression of melanin-concentrating hormone genes in the rainbow trout brain.

Salmonids, a group of tetraploid fish including salmon and trout, produce the vertebrate neuropeptide melanin-concentrating hormone (MCH) in a group of hypothalamic magnocellular neurons in the nucleus lateralis tuberis (NLT). NLT neurons project both to the brain and to the neural lobe of the pituitary gland from where MCH is released into the circulation to play a central role in camouflage (+/- stress). We have cloned and sequenced the MCH1 and MCH2 genes from the rainbow trout, Oncorhynchus mykiss, and used the data firstly to examine the position of O. mykiss in salmonid phylogeny, and secondly to enable central nervous system MCH1 and MCH2 gene expression to be mapped. In the immature adult female trout brain, only MCH2 was detectable at the hybridization stringency used. In addition to the known location of MCH-positive neurons, immunocytochemistry and in situ hybridization histochemistry revealed a previously undescribed nucleus of MCH-positive neurons located more dorsal and posterior to those of the NLT, over the paraventricular organ of the lateral ventricular recess. Axons from this second group of MCH neurons project dorsally into the brain, while a few extend down toward the lateral ventricle near the paraventricular organ. They make little, if any, direct contact with the neurohypophysis, and thus may subserve a central function, unrelated to hormonal colour regulation.

Amino Acid Sequence↗
PubMed1995

The influence of volumetric tumor doubling time, DNA ploidy, and histologic grade on the survival of patients with intracranial astrocytomas.

PURPOSE: To improve the prediction of individual survival in patients with intracranial astrocytomas through the analysis of volumetric tumor doubling time (VDt) and DNA ploidy. METHODS: A pilot study was retrospectively conducted on a group of 25 patients with intracranial astrocytomas in whom recurrent and/or progressive disease was observed on serial contrast-enhanced CT or MR examinations. VDt was computed using two or more data points from a semilogarithmic plot of tumor volume versus time. Size-adjusted survival was calculated using a method based on VDt and initial tumor volume to decrease the lead time bias attributable to differing tumor sizes at presentation. RESULTS: Slower VDt was associated with significantly longer survival and size-adjusted survival as determined by a univariate Cox proportional hazard analysis. Aneuploidy was a significant indicator of poor survival. Aneuploid and multiclonal astrocytomas had poor size-adjusted survivals compared with diploid astrocytomas. Grade IV astrocytomas had significantly poorer survival and size-adjusted survival compared with lower grades (I to III), which individually were not significantly correlated. However, grade IV histology was not a significant independent predictor of size-adjusted survival in a multivariate Cox model, whereas VDt and DNA ploidy remained significant. VDt also had a significant direct linear correlation to survival and size-adjusted survival. CONCLUSIONS: VDt and DNA ploidy were more sensitive than histologic grading as indicators of individual survival. Initial tumor size needs to be considered when staging and assessing survival in patients with intracranial astrocytomas.

Adolescent↗
PubMed1994

Extreme population structuring in the threatened ghost bat, Macroderma gigas: evidence from mitochondrial DNA.

The ghost bat, Macroderma gigas, has undergone a major range contraction and is currently restricted around a few, highly disjunct maternity sites. The amount and distribution of mitochondrial DNA (mtDNA) variation within extant populations has been used to assess levels of current and historical maternal gene flow between these populations. An approximately 330 base pair fragment spanning a hypervariable area of the mtDNA control region was amplified and sequenced by using 22 individuals from four current ghost bat populations. The mean sequence diversity of 4.5% between populations was six times higher than that within populations (0.68%), and alleles within populations were monophyletic. Restriction enzyme analysis of amplified products from an additional 100 individuals revealed fixed allelic differences in the distribution of control region genotypes between the four populations. It is suggested that this extreme genetic subdivision is a consequence of long-term female philopatry. For the purposes of management each population should be treated as an independent entity. The depth of the genetic structuring suggests that the isolation of extant populations preceded the historical range contraction.

Alleles↗
PubMed1994

Sequence and expression of a monkey testicular transcript encoding tMDC I, a novel member of the metalloproteinase-like, disintegrin-like, cysteine-rich (MDC) protein family.

Full-length clones encoding a novel member of the metalloproteinase-like, disintegrin-like, cysteine-rich (MDC) family of proteins have been isolated from a monkey (Macaca fascicularis) testicular cDNA library. The encoded putative 82 kDa transmembrane protein (tMDC I) shows striking sequence similarity to other members of the MDC family including rat and monkey EAP I, guinea-pig PH-30 and human MDC protein, as well as a number of snake venom components.

Amino Acid Sequence↗
PubMed1994

Genetic evidence for an additional member of the metalloproteinase-like, disintegrin-like, cysteine-rich (MDC) family of mammalian proteins and its abundant expression in the testis.

Full-length clones have been isolated from a Macaca fascicularis cDNA library corresponding to a 2.65 kb mRNA present at high steady state levels in the testis. Sequence analysis suggests that the predicted translation product, tMDC II protein, represents a novel member of the metalloproteinase-like, disintegrin-like, cysteine-rich (MDC) family of mammalian proteins.

ADAM Proteins↗
PubMed1994

Sequence analysis of a mammalian phospholipid-binding protein from testis and epididymis and its distribution between spermatozoa and extracellular secretions.

The cellular origin of a soluble phospholipid-binding protein (PBP) in rat testicular and epididymal secretions has been investigated genetically and immunologically. PBP is ubiquitous in tissue cytosols but is not present in blood serum, lymph or milk. The relatively large amounts present in cauda epididymal plasma (CEP) and rete testis fluid suggested therefore that it may be secreted specifically by these tissues. However, when PBP cDNAs from testis and epididymis were cloned and sequenced, they did not contain a signal peptide and only one size of transcript was obtained on Northern blots of RNAs from liver, brain, placenta, testis and epididymis. Moreover, PBP could not be detected in sperm-free CEP from castrated, androgen-stimulated animals or in medium from Sertoli cell cultures. Spermatozoa, on the other hand, contained significant amounts of PBP that could be solubilized by washing cells in dissociating reagents or high-salt solutions. These results indicate that, contrary to previous interpretations, PBP is not secreted by classical pathways in either the testis or epididymis but that its presence in CEP and rete testis fluid is attributable largely to release from spermatozoa. Thus, spermatozoa have a significant influence on the composition of CEP as well as on the secretory and absorptive activity of the epididymal epithelium. A possible role for PBP in membrane biogenesis and maintenance of antigen segregation in spermatozoa is discussed.

Amino Acid Sequence↗
PubMed1994

Sequence analysis of the L1 metallo-beta-lactamase from Xanthomonas maltophilia.

The amino acid sequence deduced from the L1 beta-lactamase gene of Xanthomonas maltophilia shows a significant variation from that of the CphA and Blm metallo-beta-lactamases of Aeromonas hydrophila and Bacillus cereus, respectively. Whilst the N-terminus of the L1 protein shows some similarity, particularly at the histidine residues previously suggested as a zinc-binding motif, the C-terminus of the protein demonstrates very little similarity. Such differences amongst this group of enzymes would argue for at least three subclasses within the Group 3 beta-lactamases. However, in order to predict their phylogenetic ancestry more sequence data are required from other possible metallo-beta-lactamases.

Amino Acid Sequence↗
PubMed1994

Guanine nucleotide exchange factor for eukaryotic initiation factor-2. Cloning of cDNA for the delta-subunit of rabbit translation initiation factor-2B.

Peptide sequence data for rabbit eIF-2B delta were obtained and used to design redundant oligonucleotides for PCR. RNA was isolated from rabbit liver and used to direct the synthesis of total cDNA. A rabbit eIF-2B delta transcript was then amplified by PCR and sequenced. The PCR product was used to isolate a clone from a rabbit liver cDNA library. RACE (rapid amplification of cDNA ends) was used to obtain further 5' sequence. Subsequently, a full length cDNA was obtained from a rabbit reticulocyte library. PCR was used to confirm that the sequence is the same for the liver factor. The sequence obtained shows strong homology to that of yeast eIF-2B delta, the GCD2 gene product.

Amino Acid Sequence↗
PubMed1994

Viral variability and serum antibody response in a laboratory worker infected with HIV type 1 (HTLV type IIIB).

Molecular clones of HIV-1 were obtained from isolates cultured from peripheral blood mononuclear cells (PBMCs) and directly from uncultured PBMCs from a laboratory worker accidentally infected with the HIV-1 laboratory strain, HIV-1(HTLV-IIIB). Envelope sequences corresponding to the first 752 amino acids of HIV-1(HTLV-IIIB) clone BH10 were obtained from clones of cultured virus and sequenced. Three env clones obtained shortly after infection differed among themselves at only seven nucleotide positions, resulting in one amino acid substitution and one frameshift mutation. These envelope sequences were as similar to the envelope sequences of various IIIB clones as the latter were to each other. env divergence increased over the course of infection. However, the overall diversity in env clones obtained two or more years after infection was still comparable to that among IIIB env clones from the original IIIB culture. Multiple clones of partial env gene sequences containing the V3 loop were also obtained directly from uncultured PBMCs by polymerase chain reaction amplification. The env sequences of these clones were generally similar to those of the cultured viruses. Within the V3 region, the earliest isolates retained the sequence of the HXB2 clone from IIIB. Clones obtained later showed a progressive divergence in V3. An A-to-T substitution within the GPGRAF sequence at the tip of the V3 loop was observed within 1 year after infection, and this mutation predominated in all subsequent isolates. Antibodies against the V3 loops of IIIB and divergent 1987 and 1990 LW isolates appeared simultaneously in laboratory worker serum and persisted with no significant differences in titer. Furthermore, neutralization studies with autologous sequential sera suggested selection for the A-to-T change in V3 was not due to V3-directed antibodies. These results demonstrate a surprising homogeneity among env sequences of HIV-1 from an infected laboratory worker, perhaps because the initial infection originated from a relatively homogeneous population of tissue culture-adapted virus.

Acquired Immunodeficiency Syndrome↗
PubMed1994

p53 gene mutations in pituitary adenomas: rare events.

OBJECTIVE: Occult pituitary adenomas are said to occur in up to 20% of random autopsy examinations, yet the only oncogene known to be associated with pituitary adenomas, gsp, is found in only 40% of somatotrophinomas, a subtype that accounts for a minority of pituitary tumours. Mutations of the p53 tumour suppressor gene are thought to be involved in the pathogenesis of as many as 50% of all human cancers, including tumours of the central nervous system. The objective of this study was to determine whether p53 gene mutations are associated with pituitary adenomas. DESIGN AND PATIENTS: Fragments of pituitary adenoma tissue from 29 patients undergoing routine hypophysectomy for pituitary tumour were coated in cryostat embedding medium and frozen at -80 degrees C within 24 hours of resection. They consisted of 9 somatotroph, 4 corticotroph, 1 mammotroph and 15 endocrinologically inactive adenomas, all of the non-invasive clinical phenotype. Sequential frozen sections were subjected to in situ hybridization analysis for anterior pituitary hormone transcripts and examined histologically to ensure that the frozen sections used to generate DNA templates for polymerase chain reaction amplification were not contaminated with non-tumour tissue. MEASUREMENTS: p53 exons 7 and 8, within which 98% of substitution mutations are thought to occur, and exons 4-6 in tumours immunopositive for p53, were amplified by polymerase chain reaction and ligated into the vector pCR2. DNA from small-scale plasmid preparations of pCR2 containing cloned p53 exons from human pituitary adenomas was sequenced using an automated fluorescence-based system (DuPont Genesis 2000) and compared with wild-type sequence. Apparent mutations were confirmed or refuted by sequencing a further 2-4 clones isolated from the same template. RESULTS: Although immunocytochemical staining patterns for wild-type p53 varied markedly between different tumours, no mutations were identified in any of the exonic sequences examined. CONCLUSIONS: p53 mutations, at least within the high mutation domains of p53, occur infrequently in human pituitary adenomas. Increased steady-state levels of p53 protein identified immunocytochemically may be a consequence of binding to other cellular proteins in these tumours.

Adenoma↗
PubMed1994

Production of cytokines by lymphocytes from spleen, mesenteric lymph node and intestinal lamina propria of pigs.

Large numbers of cells can be recovered from pig intestine with phenotypes suggesting lamina propria rather than intraepithelial origin. Following activation with concanavalin A these cells produced a T-cell growth factor (TCGF) activity which was not inhibited in the presence of a monoclonal antibody recognizing pig interleukin-2 receptors (IL-2R). In contrast, the activity of recombinant human IL-2 and of supernatants from activated spleen cells was almost entirely inhibited by anti-IL-2R. The failure of anti-IL-2R to inhibit the activity of lamina propria-derived TCGF was not apparently owing to interference by soluble receptor with binding of monoclonal to target blast cells as no effect of supernatants on binding was observed. The results suggest that cells derived from the pig intestinal lamina propria fail to produce IL-2 following polyclonal activation in vitro. Consistent with this finding, IL-2 transcripts could be detected by polymerase chain reaction (PCR) following reverse transcription of mRNA derived from spleen and from mesenteric lymph node but not lamina propria lymphocytes, while IL-4 cDNA could be detected from all three sources.

Animals↗