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L D Johnson

Publications and source records attributed to L D Johnson.

At least 19 recordsLinked to original sources
PubMed1995

Chromatin organization, meiotic status and meiotic competence acquisition in mouse oocytes from cultured ovarian follicles.

Changes in chromatin organization, meiotic status and the development of meiotic competence in oocytes retained within mouse ovarian follicles from day 0 to day 6 in culture were examined. The effects of exposure for 24 h to human luteinizing hormone (hLH) during the last day in culture was also determined. Preantral follicles from 22- to 24-day-old (prepubertal) mice develop antra and undergo significant growth from day 0 to day 4 in culture, after which the growth rates slow. The statistical significance of meiotic progression was examined using exact logistical regression analysis, which is particularly useful when the data are sparse and unbalanced. The transition from rimmed to unrimmed germinal vesicle stages was found to occur between day 2 and day 4 of follicle culture and was not influenced by exposure to hLH. Treatment with hLH caused a significant increase in the proportion of intrafollicular oocytes resuming meiosis. Assays of meiotic competence performed in vitro in oocytes retrieved from cultured follicles demonstrated that the transition from an unrimmed to a rimmed state is closely coincident with the acquisition and expression of meiotic competence. Forty-six per cent of competent oocytes from follicle cultures at day 3 progressed to metaphase II. These results indicate that the follicle culture system used in these studies supports the transformation of enclosed oocytes from a precompetent to a competent state and can maintain meiotic arrest for up to 6 days in culture. However, an increasing proportion of oocytes exhibit abnormal meiotic progression with continued follicle culture beyond 4 days.

Animals↗
PubMed1994

Proliferative activity of intrinsic cell populations in the normal human kidney.

The proliferative activity of various normal human renal cell populations is unknown. Recently, antibodies to cell proliferation-associated nuclear proteins, such as proliferating cell nuclear antigen (PCNA) and KI-67, which are applicable to archival paraffin sections, became available. With antibodies to PCNA and Ki-67 after microwave pretreatment of the paraffin sections, the proliferation indexes (ratio of positive nuclei with PCNA and Ki-67 antibodies/all nuclei counted x 100, i.e. percentage of positive cells) of 12 different intrinsic renal cell populations in 20 normal human kidneys have been determined. The following proliferation indexes (percentages of positive cells) were found with the PCNA and the Ki-67 antibodies, respectively: proximal tubular epithelium, 0.22, 0.24; thin limb of Henle, 0.29, 0.30; thick ascending limb of Henle, 0.32, 0.29; distal tubular epithelium (distal convoluted tubules and cortical collecting ducts, 0.33, 0.44; medullary collecting ducts, 0.32, 0.3; glomerular mesangial cells, 0.07, 0.12; glomerular visceral epithelial cells, 0.04, 0.08; glomerular parietal epithelial cells, 0.07, 0.1; glomerular capillary endothelium, 0.42, 0.47; peritubular capillary endothelial cells, 0.38, 0.43; endothelium of large intrarenal vessels (arteries and veins), 0.09, 0.12. Thus, normally capillary endothelium (glomerular and peritubular) appears to have the highest proliferation index in the human kidney by these techniques. These results indicate major variation in the proliferative activity of normal human renal cell populations, along with a significant correlation between PCNA and Ki-67 staining. Furthermore, this study provides normal values for the proliferative activity of different human renal cell populations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

In situ DNA hybridization study of 'primary' cytomegalovirus (CMV) oophoritis.

We report the case of a 50 year old woman with metastatic breast carcinoma refractory to chemotherapy who died of candidal septicemia after autologous bone marrow transplantation. Although there was no apparent active cytomegalovirus (CMV) infection (negative cultures and serology for active infection), autopsy revealed histologic evidence of CMV inclusions limited to both ovaries. DNA in situ hybridization was performed on multiple organs, and additional foci of infection in one fallopian tube and the adrenal glands were detected. Previous reports of isolated CMV oophoritis may represent sampling error. An ascending route of infection is suggested. Tubo-ovarian changes due to CMV infection may occur more frequently than suspected; they are difficult to diagnose because even actively CMV infected cells may not be detected by routine histology alone, and because, after the active infection 'heals', no evidence of the virus can be found on histologic examination.

Adrenal Gland Diseases↗
PubMed1994

Renal interleukin-1 expression during endotoxemia and gram-negative septicemia in conscious rats.

Endotoxin-induced cytokines such as interleukin-1 (IL-1) and tumor necrosis factor (TNF) are thought to contribute to the proinflammatory effects of endotoxin in gram-negative infections. Using a conscious rat model of sepsis, induced by intravenous challenge with LD95 doses of endotoxin (n = 24) or live Escherichia coli (E. coli) (n = 24), we examined frozen sections of kidney at various intervals for evidence of IL-1 alpha and TNF alpha expression. A transient glomerular endothelial IL-1 alpha expression was demonstrated at 30 and 90 min after initiation of the sepsis in both endotoxin and E. coli-treated animals using immunohistochemistry. The endothelial IL-1 alpha expression as determined by immunohistochemistry occurred at the same time as IL-1 alpha mRNA expression, as determined by Northern blot analysis. The glomerular endothelial IL-1 alpha expression coincided with a slight but significant increase in the number of the glomerular polymorphonuclear leukocytes as identified by naphthol AS-D chloroacetate esterase enzyme histochemical reaction. Glomerular endothelial IL-1 alpha expression was virtually absent by 180 and 360 min. No TNF alpha expression was detected in the renal tissues at any time interval. Neither alpha-naphthyl acetate esterase-positive nor acid phosphatase-positive monocytes/macrophages were identified in the glomeruli. Our findings provide direct in vivo evidence that the IL-1 alpha gene product is expressed locally in the kidney by glomerular endothelial cells in this septic rat model.

Animals↗
PubMed1994

Lack of suppressed renal thrombomodulin expression in a septic rat model with glomerular thrombotic microangiopathy.

BACKGROUND: The thrombomodulin-dependent protein C anticoagulant pathway plays a major physiologic role in the down-regulation of the coagulation process. In cell culture, inflammatory cytokines or endotoxin can down-regulate endothelial thrombomodulin (TM) suggesting that suppressed TM expression may contribute to thrombotic complications noted in Gram-negative sepsis. EXPERIMENTAL DESIGN: In the present study, we have examined TM expression in the kidneys of septic rats utilizing indirect immunofluorescence and have quantified TM antigen and TM activity in extracts of the same kidneys by enzyme-linked immunosorbent assays and protein C activation assays, respectively. Conscious Sprague-Dawley rats were injected intravenously with LD95 doses of live E. coli (N = 30), or endotoxin (N = 30). Control animals (N = 30) were injected with equivalent volumes of saline. The rats were killed 30, 90, 180, 360, and 720 minutes after the initiation of sepsis. RESULTS: Glomerular capillary thrombosis developed by 180 minutes in approximately half of the animals after the initiation of sepsis. We failed to demonstrate suppressed TM expression in the kidneys of septic animals using immunofluorescence. Neither enzyme-linked immunosorbent assays, nor protein C activation assays showed decreased levels in TM antigen expression or activity at different time points during the sepsis. CONCLUSIONS: These results indicate that suppressed TM expression does not contribute to the development of the glomerular capillary thrombosis in this septic rat model.

Animals↗
PubMed1994

Absence of association between cytomegalovirus infection and obliterative transplant arteriopathy in renal allograft rejection.

Cytomegalovirus (CMV) was recently identified, using in situ hybridization, in the coronary arteries of patients with cardiac transplant rejection, suggesting a role of CMV in the development of obliterative transplant arteriopathy in cardiac allografts. We sought to verify this observation by examining arteries in kidney transplants with intimal thickening due to chronic rejection. Eleven renal biopsies and 13 nephrectomies from 24 patients, all showing obliterative transplant arteriopathy, were collected for this study. Of these patients, six were seropositive for CMV before transplantation, three were identified as seropositive following renal transplantation, nine had no evidence of CMV infection, and clinical data were not available for an additional six patients. Paraffin-embedded renal sections were examined for the presence of CMV by immunohistochemistry in situ hybridization and polymerase chain reaction. By these methods, only one case (1/24) was demonstrated to have CMV infected cells in the renal interstitium, tubules, and glomeruli, but none (0/24) showed CMV to be located in any of the renal arteries or arterioles. Thus, our results suggest that obliterative transplant arteriopathy can occur in the absence of demonstrable CMV and is probably unrelated to direct CMV infection of the graft.

Adult↗
PubMed1992

Is cytomegalovirus associated with renal disease in AIDS patients?

Although it has been suggested that cytomegalovirus (CMV) infection of the kidney might facilitate the development of human immunodeficiency virus-associated nephropathy (HIVAN) or other morphologic renal changes in patients with AIDS, no systematic study has been performed on kidneys from AIDS patients. We examined 75 autopsy kidneys, two renal biopsy specimens, and a nephrectomy specimen from 78 HIV-infected patients (five with HIVAN) for the presence of CMV. Immunocytochemistry (ICC) utilizing a monoclonal antibody against the late antigen of CMV and in situ hybridization (ISH) with a biotinylated DNA probe for CMV sequences were used. The detection system for both ICC and ISH was streptavidin-conjugated alkaline phosphatase with Fast Red TR chromogen. CMV was detected in only 10 of the 78 kidneys examined (12.8%): eight by both methods, one by ISH only, and another by ICC only. All 10 positive kidneys were obtained from autopsies of patients with AIDS. The average number of positive cells (in approximately 15 x 10 mm sections) was 22 with ICC and 10 with ISH. Glomerular intracapillary cells (possibly endothelial cells) were the most commonly stained, followed by positive cells in the interstitium and peritubular capillaries. Relatively few tubular epithelial cells were stained. The majority of positive cells by either ICC or ISH did not show nuclear or cytoplasmic inclusions; however, only two of the 10 positive kidneys did not contain cells with typical Cowdry type-A intranuclear CMV inclusions. The most frequent pathologic finding in the kidneys positive for CMV by either ICC or ISH was acute tubular necrosis (in six of 10, 60%).(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS-Associated Nephropathy↗
PubMed1991

Quality of oocytes from superovulated rhesus monkeys.

The parameters, serum oestradiol (E2) response, follicle size and cumulus morphology, which are commonly used to determine in-vivo oocyte maturation in human in-vitro fertilization and embryo transfer (IVF-ET) programmes, were shown to be unreliable predictors of maturation of rhesus oocytes. In two groups of rhesus, one stimulated with pregnant mares' serum gonadotrophin (PMSG) and human chorionic gonadotrophin (HCG) and the other with human menopausal gonadotrophin (HMG) and HCG, the three parameters varied widely within and between protocols. Triple fluorochrome staining (TFS) for chromatin, microtubules and filamentous actin (f-actin) in oocytes at the time of collection and following 24 h in culture showed major differences in their maturation both in vivo and in vitro following priming with PMSG and HMG. In evaluating IVF protocols, TFS provides a valuable assay for the meiotic status of fixed oocytes of non-human primates.

Animals↗
PubMed1990

When an institution dies. Nursing's role in closing a facility.

1. This article documents the development of a nursing role to support the staff and faculty of a state residential school for adolescents during closure of that institution. 2. The process of institutional closure resulted in increased ambiguity and need to redefine social expectations and responsibilities. Supportive nursing intervention facilitated the transition. 3. Theory and intervention associated with loss through death and dying can be appropriately adapted for use in nursing intervention during loss experienced with organizational death and institutional closure. 4. Because the meaning and experience of loss during institutional closure involves everyone and does not occur in a uniform or linear manner, nurses' roles must be flexible, responsive to contextual change, and introspective, as well as analytical and supportive.

Adaptation, Psychological↗
PubMed1989

The effect of heterologous gonadotropins on the fecundity of rhesus monkeys.

Ovarian stimulation with heterologous gonadotropins over a period of a single month did not depress the fecundity or fecundability of 50 rhesus monkeys as compared to 60 untreated monkeys in a timed breeding colony. The birth rates, seasonality of births, interbirth intervals, and waiting time to the next pregnancy were not significantly different before treatment, after treatment, or among the untreated. The stillbirth rate was not increased after treatment.

Animals↗
PubMed1989

Incontinence.

1. Urinary incontinence is a significant cause of disability and dependency among the elderly, and is frequently cited as the major precipitant in long-term institutionalization. 2. Incontinent elderly view their condition as a significant symbol of loss of control as well as self-esteem, and is discussed by them in terms of infantilization. 3. Potential advantages of research and intervention and urinary incontinence include improved well-being of patients, relief of family burden, and cost benefit to society. 4. Evaluating behavioral treatment for incontinence remains an important nursing challenge due to the diversity of the incontinent elderly population in terms of their urinary tract pathophysiology; neurologic, cognitive, and functional status; and their environmental setting.

Aged↗
PubMed1987

The relative binding affinity of diethylstilbestrol to uterine nuclear estrogen receptor: effect of serum and serum albumin.

The relative binding affinity (RBA) of diethylstilbestrol (DES) was determined in nuclear fractions of the rat uterus. DES displayed a two- to threefold greater affinity (RBA = 245 +/- 36) than estradiol (RBA = 100) for nuclear E receptor. The RBA of DES to nuclear E receptor was lowered significantly in the presence of rat serum (43 +/- 1) or human serum (52 +/- 7). Dilution of human serum resulted in a progressive increase in the RBA of DES which approached that observed in the absence of serum. Addition of purified human serum albumin mimicked the decrease in RBA of DES that was observed with serum. The IC50 of estradiol was not changed in the presence of either rat serum or albumin. These data show that DES possesses a greater affinity for nuclear E receptor than estradiol and that serum albumin can modulate DES binding to uterine E receptor.

Animals↗
PubMed1986

Photoreversal-dependent release of thymidine and thymidine monophosphate from pyrimidine dimer-containing DNA excision fragments isolated from ultraviolet-damaged human fibroblasts.

To elucidate the enzymatic excision-repair process operative on cyclobutane-type pyrimidine photodimers in human dermal fibroblasts, we have examined excised dimer-containing material recovered in the trichloroacetic acid soluble fraction from far-ultraviolet-irradiated (254 nm, 40 J m-2) and incubated (24 h) cell cultures. The excised DNA photoproducts were found in oligonucleotide fragments with an estimated mean chain length of approximately 3.7 bases. Exposure of these isolated excision fragments, labeled with [3H]thymidine (dT), to a secondary, dimer-photoreversing fluence of far-UV (5.5 kJ m-2) resulted in the release of free dT and thymidine monophosphate (TMP). Photorelease of these two radioactive species was measured by high-performance liquid chromatography, with TMP being detected as the increase in dT following bacterial alkaline phosphatase treatment. These data imply that the photoliberated dT and TMP moieties were attached to the excision fragments solely by the cyclobutane ring of the dimer. No evidence was obtained for the photoliberation of free thymine, thus corroborating a conclusion reached by others that the excision of dimers in human cells is not initiated by scission of an intradimer N-glycosyl bond. The sum of the tritium label recovered in dT plus TMP corresponded to approximately 40% of that disappearing from thymine-containing dimers on photoreversal, suggesting that in about 80% of the isolated excision fragments the dimer is located at one end of the oligonucleotide and contains a break in its internal phosphodiester bond.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Amino acid sequences of mouse and human epidermal type II keratins of Mr 67,000 provide a systematic basis for the structural and functional diversity of the end domains of keratin intermediate filament subunits.

From the nucleotide sequences of specific cDNA clones, we present partial amino acid sequences (75-90% of the total) of 67-kDa type II keratin subunits expressed in terminally differentiating mouse and human epidermis. Analysis of the sequence information reveals that their secondary structures conform to the pattern common for all intermediate filament (IF) subunits. Together with the previously published sequence of the mouse 59-kDa type I keratin (Steinert, P. M., Rice, R. H., Roop, D. R., Trus, B. L., and Steven, A. C. (1983) Nature 302, 794-800) these data allow us to make comparisons between two keratins which are coexpressed in an epithelial cell type and which coassemble into the same IF. Moreover, these comparisons suggest a systematic plan for the general organization of the end domains of other keratin subunits. We postulate that each end domain consists of a set of subdomains which are distributed with bilateral symmetry with respect to the central alpha-helical domain. Type II (but not type I) keratins contain short globular sequences, H1 and H2, immediately adjacent to the central domain, that have been conserved in size and sequence and which account for most of the difference in mass between coexpressed type II and type I keratins. These are flanked by subdomains V1 and V2 that are highly variable in both length and sequence, often contain tandem peptide repeats, and are conspicuously rich in glycines and/or serines. At the termini are strongly basic subdomains (N and C, respectively) that are variable in sequence. Among keratins of a given type, their variability in mass appears to reside in the size of their V1 and V2 subdomains. However, coexpressed type I and type II keratins have generally similar V1 and/or V2 sequences. By virtue of the ease with which large portions of these subdomain sequences can be removed from intact keratin IF by limited proteolysis, we hypothesize that they lie on the periphery of the IF where they participate in interactions with other constituents of epithelial cells.

Amino Acid Sequence↗
PubMed1985

Structure of a gene for the human epidermal 67-kDa keratin.

We present the structure and nucleotide sequence of a gene encoding the human epidermal 67-kDa keratin. Three genomic clones were isolated from a lambda Charon 4A human genomic library by hybridization to a specific cDNA probe. One clone of 12.3 kilobase pairs was shown by R-loop, DNA sequence, and primer-extension analyses to encode an entire gene of about 6.25 kilobase pairs. Of eight identified introns, seven are located within the region that encodes the central coiled-coil alpha-helical domain of the protein. Except for one intron located at the end of the region encoding this domain, these do not delineate apparent structural subdomains. The positions of five of the introns exactly coincide with the positions of introns previously reported in the hamster gene for the intermediate filament protein vimentin [Quax, W., Egberts, W.V., Hendricks, W., Quax-Jeuken, Y. & Bloemandal, H. (1983) Cell 35, 215-233]. These findings suggest that the human 67-kDa keratin and vimentin genes arose from a common ancestral gene.

Amino Acid Sequence↗
PubMed1984

Occurrence of mammary tumors in rats after exposure to tritium beta rays and 200-kVp X rays.

The RBE for tritium was estimated in reference to 200-kVp X rays, using acceleration of breast tumor appearance in the female Sprague-Dawley rat as the end-point. Chronic X-ray doses of 0.3-2.0 Gy were delivered over 10 days. Intraperitoneal injections of tritiated water ranging in concentrations from 45 to 370 MBq/100 g body wt were administered, followed by four additional injections at 2-day intervals and half of the initial concentrations. Seventy-five percent of the total tritium dose was delivered to the mammary gland within the first 10 days and 95% within the first 20 days after the start of the tritium exposure. RBE estimations were based on various criteria including the tumor incidence per Gy at 450 days postirradiation and the time required to induce tumors in 50% of the animals at risk. The results suggest that tritium beta rays are about 1.1-1.3 times more effective than chronic 200-kVp X rays for acceleration of the appearance of rat mammary tumors. However, the uncertainties involved in these calculations are such that the effects of tritium beta rays could not be reliably distinguished from those of chronic 200-kVp X rays. Measured differences in RBE values were slightly larger for the comparison between acute and chronic X rays than for the comparison between chronic tritium beta rays and chronic X rays.

Animals↗