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D Spencer

Publications and source records attributed to D Spencer.

At least 91 records · Page 5Linked to original sources
PubMed1990

Renal epithelial amino acid concentrations in mercury-induced and postischemic acute renal failure.

The concentration of 18 alpha-amino acids (AAs) in plasma and renal cortical cell water were measured 3 or 24 hr after 1 hr of unilateral renal artery clamping or 24 or 48 hr after 15 mg/kg body weight HgCl2 injection sc as a test of epithelial integrity. Cellular glycine (Gly), hydroxyproline (Hpr), ornithine (Orn), phenylalanine (Phe), serine (Ser), and tryptophan (Trp) concentrations were depressed 24 hr after HgCl2 (p less than 0.05), but the remaining 12 AAs were not distinguishable from control despite the presence of severe renal failure. ARginine (Arg), glutamic acid (Glu), and valine (Val) also were decreased (P less than 0.05) 24 hr later, but concentrations of half of all measured AAs were still normal. Cellular alanine (Ala), Arg, Glu, Gly, Phe, and Ser concentrations were decreased 3 hr after ischemia, p less than 0.05, but 12 AAs were unchanged and only Arg, Phe, Ser, and threonine (Thr) were reduced 24 hr after ischemia was reversed. Concentrations of even the most affected AAs remained notably higher than in plasma in both forms of acute renal failure (ARF). Total loss of AAs from a small proportion of tubular cells would be hidden by essentially normal concentrations in the rest, and such losses may well have occurred. Unless cellular AAs in ARF are almost completely bound, however, the well-maintained cell:plasma AA concentration ratios indicate that cellular energetics were adequate for AA uptake and that epithelial permeability to AAs in the vast majority of cells was not greatly disturbed. Such findings suggest that most of the epithelium, although seriously damaged, had remained viable.

Acute Kidney Injury↗
PubMed1990

Cryopreservation of human brain tissue.

Tissues from products of conception were examined to determine the feasibility of obtaining viable neural tissue after suction abortion at 9-12 weeks of gestation. The ventral mesencephalon, a prototype region whose maturation can be monitored and which is a potential tissue for transplantation, was identified in 32 of 120 cases. The tissue was then screened for the presence of infectious agents, while being held at -196 degrees C in cryopreservative solutions. Three of 32 specimens were found to be contaminated by normal vaginal bacteria; all other viral, fungal, and mycoplasma testing was negative. Thawed brain fragments retained high viability after storage in liquid nitrogen and when grown in vitro exhibited neuronal morphology, tyrosine hydroxylase immunoreactivity, and dopamine production. We have demonstrated that human fetal brain tissue can be cryopreserved in a manner which not only retains viability but allows normal phenotypic differentiation after thawing.

Brain↗
PubMed1990

Anterior segment upper lobe tuberculosis in the adult. Occurrence in primary and reactivation disease.

Nine patients with pulmonary tuberculosis involving predominantly or exclusively the anterior segment of one or both upper lobes were seen over a five-year period. The incidence of anterior segment upper lobe tuberculosis was 6.3 percent of 142 patients presenting with pulmonary tuberculosis during the same time period. Five of the nine patients with anterior segment upper lobe involvement had reactivation disease. An increased incidence of advanced age, diabetes, associated malignant neoplasms, alcoholism, and steroid use were noted in those patients with anterior segment involvement, although only the occurrence of diabetes was statistically significant. We suggest vigilance with regard to the diagnosis of tuberculosis in patients who are elderly, diabetic, or alcohol abusers, particularly where the roentgenographic appearance of anterior segment upper lobe involvement would tend to favor an alternative diagnosis.

Adult↗
PubMed1990

Ipsapirone: evidence for efficacy in depression.

Sixty-five inpatients of a psychosomatic hospital in the Federal Republic of Germany with the diagnosis of anxiety neurosis (n = 31) or neurotic depression (n = 34) as defined by the International Classification of Disease (ICD-9), were randomized to a 4-week course of ipsapirone at 7.5 mg t.i.d. or placebo in a prospective, double-blind clinical trial to assess safety, tolerability, and efficacy. This article reports the efficacy results for those patients with the diagnosis of neurotic depression. The primary efficacy variable for patients with neurotic depression was the change from baseline in the Hamilton Rating Scale for Depression (HAM-D) at 4 weeks of treatment. Considering all of the randomized patients with neurotic depression (n = 34, the intent-to-treat population), the mean change from baseline in the HAM-D at Week 4 (observed cases) was -13.13 +/- 6.06 (n = 16) for the ipsapirone group, and -3.19 +/- 5.99 (n = 16) for the placebo group (p less than .001). A parallel analysis of the change from baseline in the Core Depression score of the HAM-D (defined as the sum of items 1, 2, 3, 7, and 8) also showed a significant treatment difference (p less than .01). Results were similar for the intent-to-treat population, last observation carried forward. Safety and tolerability were evaluated for all study patients independent of diagnosis. Treatment-emergent events (n = 65) were reported by 76 percent of patients treated with ipsapirone (n = 33) and by 38 percent of patients treated with placebo (n = 32).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Predominant variable region gene usage by gamma/delta T cell receptor-bearing cells in the adult thymus.

Previous studies have indicated that the diversity of gamma genes expressed by gamma/delta-bearing murine T cells is limited, but comparable information concerning the expressed diversity of delta genes is lacking. In this study, we have investigated the rearrangement and expression of delta and gamma genes in T cell hybridomas that express gamma/delta T cell receptors. Three productive delta chain cDNA clones were isolated (delta 7.3, delta 7.1, and delta 2.3) that encode new variable region sequences. Two of the delta cDNAs differ significantly from those observed in the V alpha repertoire. In addition, one cDNA expressed a new J delta region (J delta 2), which was localized between J delta 1 and C delta genes. Using these and other delta gene probes and gamma gene probes, we found that five independent hybridomas expressed four different V delta s and three different V gamma s. However, analysis of an enriched population of gamma/delta-expressing cells from the adult thymus suggests that only a few V delta genes and one V gamma gene are used by the majority of the cells. These results suggest that important components of receptor chain that contribute to specificity (i.e., the germline V gene sequences) are relatively nondiverse in the thymic gamma/delta population.

Amino Acid Sequence↗
PubMed1988

Monitoring the fate of dietary proteins in rumen fluid using gel electrophoresis.

1. When fractionated by sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE), strained rumen fluid from sheep fed on pelleted lucerne (Medicago sativa) hay showed no major protein components that stain with Coomassie Blue. This feature made it possible to monitor the fate of individual polypeptides within a protein mixture incubated in rumen fluid in vitro. 2. Extracts from a number of seed meals (sunflower (Helianthus annuus), lupin (Lupinus angustifolius), rape (Brassica napus) and pea (Pisum sativum L.)), as well as casein and bovine serum albumin, were examined in this system. The protein components of each seed type showed a wide range of resistances to degradation. One protein in pea seeds (pea albumin 1), which is particularly rich in cysteine, was almost as resistant to rumen degradation as bovine serum albumin. 3. Analysis of synthetic-fibre-bag experiments by SDS-PAGE showed that the rate of loss of total protein from solid meal residues does not provide an index of the resistance of individual protein components of the meal to rumen degradation. While there was no qualitative change in the protein profile of residual pea-seed meal inside a synthetic-fibre bag, there was considerable variation in the rate at which individual, solubilized protein components were degraded in the surrounding rumen fluid.

Animals↗
PubMed1986

Gene structure, protein structure, and regulation of the synthesis of a sulfur-rich protein in pea seeds.

Two low molecular weight pea seed albumins (Mr approximately 6000 and approximately 4000) have been characterized by protein, cDNA, and gene sequencing. Both proteins are encoded by separate regions of the same mRNA species. The initial translation product is a preproprotein from which a signal sequence is removed co-translationally. The resultant proprotein (PA1) is then cleaved post-translationally to yield the mature form of the two albumins (PA1a and PA1b). Comparison of cDNA and protein sequences suggests that at least four different PA1 genes are expressed in the pea genome. Both PA1a and PA1b have an unusually high cysteine content (7.5 and 16.2%, respectively). Pea seeds developing under suboptimal levels of sulfur nutrient supply contain reduced levels of PA1 mRNA and accumulate greatly reduced levels of PA1a and PA1b in the mature seed. In vitro transcription studies showed that this reduced level of PA1 mRNA resulted from reduced post-transcriptional stability rather than an altered rate of transcription of the PA1 gene. In contrast, during normal seed development, the level of PA1 mRNA seems to be under transcriptional control. Sequence comparisons reveal some homology between PA1 and a number of low molecular weight proteins from seeds of a wide range of mono- and dicotyledonous plants.

Albumins↗
PubMed1986

Timely and welcome.

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Education, Nursing↗
PubMed1986

Effects of simultaneous vs sequential stimulus presentation on memory performance following temporal lobe resection in humans.

This study examines the differential effects of simultaneous vs sequential stimulus presentation on performance of a visuo-spatial memory task in patients following unilateral temporal lobectomy for relief of complex-partial seizures. Eleven subjects with surgical resection of the left temporal lobe, 13 subjects with surgical resection of the right temporal lobe, and 12 normal controls were examined. Results indicate that both the Right and the Left surgical groups were impaired on the visuo-spatial memory task employed. Further, the Right resection group was significantly more impaired for the recall of stimuli presented in the sequential condition as compared to the simultaneous condition.

Adult↗
PubMed1985

Transcriptional and post-transcriptional regulation of storage protein gene expression in sulfur-deficient pea seeds.

We have used in vitro transcription in isolated pea nuclei to determine whether the expression of genes for the seed storage proteins legumin and vicilin is regulated transcriptionally or post-transcriptionally in response to changing sulfur status in the developing seed. During the first 48 h of recovery from S deficiency, transcription of legumin genes increased by two-fold whereas the level of legumin mRNA increased 20-fold in the same period. Vicilin gene transcription decreased during recovery, consistent with a gradual decrease in mRNA levels. We conclude that regulation of legumin mRNA levels in response to changing S status is post-transcriptional, whereas that of vicilin mRNA is transcriptional. In contrast, during normal plant development the expression of both of these gene families appears to be under transcriptional control.

Gene Expression Regulation↗
PubMed1985

Premedical syndrome.

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Education, Premedical↗
PubMed1985

Pectoralis major myocutaneous reconstruction of the anterior skull base.

It was once believed that prognosis for many patients with neoplasms of the anterior skull base was hopeless. Now, however, craniofacial resection of these lesions has been curative for many patients. Massive resections of the anterior skull base pose many potentially life-threatening complications. Cerebrospinal fluid leakage with meningitis is especially troublesome when previous radiation therapy compromises wound healing. In such circumstances local tissue flaps and skin grafting may not provide reliable separation of the brain from the nose. The pectoralis major flap was utilized in eight patients undergoing anterolateral resection of the skull base. Several major advantages of this technique include: 1. reliable closure of the subarachnoid space; 2. acceptable cosmesis; 3. rapid wound rehabilitation, allowing early postoperative radiation therapy when necessary.

Adenocarcinoma↗