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Biomedical subjects

J Brock

Publications and source records attributed to J Brock.

At least 55 records · Page 3Linked to original sources
PubMed1995

Erythropoietin induces biphasic activation of p70S6k: evidence for a different regulation of early and late phase of activation.

The murine erythroleukaemia cell line HCD-57 proliferates in response to erythropoietin. Stimulation of erythropoietin-deprived cells with the cytokine induces the phosphorylation and biphasic activation of the 70,000 M(r) S6 kinase. Two peaks of enzyme activity were observed after 30 and 120 min, respectively. Early and late phase of activation differ in their sensitivity to the protein kinase C inhibitor staurosporine suggesting different regulatory mechanisms.

Alkaloids↗
PubMed1995

Immunohistochemical and glycohistochemical localization of the beta-galactoside-binding S-type lectin in human placenta.

The localization of the beta-galactoside binding lectin was studied immunohistochemically on acetone-fixed cryostat sections of full-term placental tissue using a biotinylated monoclonal antibody and glycohistochemically applying biotinylated asialofetuin and lactosylated bovine serum albumin. On blots of placental tissue lysates the lectin is recognized by the biotinylated lactosylated bovine serum albumin. The glycoconjugate recognition of the lectin on blots was inhibited in the presence of 0.1 M lactose showing the specificity of the interactions. The anti-lectin monoclonal antibody stained syncytiotrophoblast and trophoblastic cells. Both reagents applied for glycohistochemistry stained syncytiotrophoblast and trophoblastic cells of placental villi and the trophoblastic layer of extraplacental membranes. A strong uniform cytoplasmic staining was characteristic for syncytiotrophoblast and to a lower extent for cytotrophoblastic cells. The localization of the lectin is discussed with respect to a possible immunosuppressive function.

Animals↗
PubMed1995

Older Alabamians System of Information and Services (OASIS): a model Title VII chapter 2 low vision rehabilitation program.

BACKGROUND: Little attention has been paid in the ophthalmic literature to programmatic issues of low vision rehabilitation services delivery. The Older Alabamians System of Information and Services (Project OASIS) is a model low vision rehabilitation program functioning within the state of Alabama. This program is funded through Title VII, chapter 2 of the Rehabilitation Act, Independent Living Services for Older Blind Individuals. The program provides a comprehensive array of independent living services, including optometric low vision evaluation and low vision devices, to persons who are older and blind. Through intergency agreements between various state agencies and private entities, OASIS is able to maximize limited resources and reduce service redundancies. METHODS: Components of the OASIS consortium are reviewed along with outcomes of participants in fiscal year 1993-94. RESULTS: In fiscal year 1993-94 1,114 persons were entered into Project OASIS. Over half (569/1,114) of individuals accepted into the program received traditional optometric low vision rehabilitation services. More than 80% (586/717) of persons were able to achieve their independent living goals. CONCLUSIONS: Through a consortium effort between aging and rehabilitative services, minimal resources have been maximized to allow older visually impaired adults to benefit from comprehensive low vision rehabilitation services.

Activities of Daily Living↗
PubMed1994

Rapid activation of the MAP kinase pathway in hematopoietic cells by erythropoietin, granulocyte-macrophage colony-stimulating factor and interleukin-3.

MAP kinases are a family of serine/threonine specific protein kinases becoming activated in response to different proliferative stimuli by phosphorylation at both threonine and tyrosine residues. We report the involvement of MAP kinases in the signal transduction of the hematopoietic growth factors erythropoietin (EPO), granulocyte macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3) in the factor dependent human erythroleukemic cell line TF-1, suggesting a crucial role of these enzymes in the regulation of proliferation of hematopoietic cells. Both time course and degree of MAP kinase activation were similar for all three cytokines. A slightly lower stimulation effect of EPO corresponds to the observation that EPO stimulated cells proliferate at a lower rate.

3T3 Cells↗
PubMed1994

[Detection of human papillomavirus DNA in formalin fixed invasive squamous cell carcinoma of the larynx with polymerase chain reaction (PCR)].

Approximately 67 different subtypes of HPVs have now been described. Regularly most of the cervical cancers are positive for HPV 16/18. Current research also indicates that HPVs may be involved in the development of benign tumours and also squamous cell cancers of head and neck. Studies establishing the presence of different HPV subtypes in oral cancers and precancers suggest the possibility of the virus as etiological factor in oral carcinogenesis too. In this study the prevalence of HPV 6/11, 16 and 18 infection and other exogenous risk factors like nicotine and alcohol in laryngeal cancers were studied. A total of 100 formalin-fixed and paraffin-embedded cancers, 41 glottic and 59 supraglottic, in patients aged 58 years, were detected by use of the E6 specific PCR for HPV DNA. Significantly more glottic cancers, 26 of 41 (63.4%), were positive for the investigated HPV's. HPV 16 was found in all positive cancers. This predominance of HPV 16 was also present in the supraglottic carcinomas, but only 10.2% (6 of 59) of the these groups were HPV positive. In both groups the patients with HPV 16 and/or 18 positive cancers, the exogenous risk factor was higher than with in HPV 16/18 negative tumours. Following infection, the virus either remains dormant or else undergoes active replication resulting in the synthesis of infectious virus. The integration of virus DNA into the host cell DNA may be the result of action of nicotine and/or alcohol. The integration event is the key of the carcinogenesis. The level of the risk factor in the patients with supraglottic tumours was significantly higher.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Inverted papilloma and its association with human papillomavirus (HPV). A study with polymerase chain reaction (PCR)].

Nasal inverted papilloma is usually a benign tumor but is associated with squamous cell carcinoma in about 10% of cases. To determine the etiological role of human papillomavirus (HPV) in inverted papilloma and to clarify the relationship between the different types of human papillomavirus and malignant transformation, we analyzed retrospectively a series of 29 formalin - fixed, paraffin-embedded cases, 3 of which had squamous cell carcinoma. A highly sensitive and specific modification of the polymerase chain reaction (PCR) was used to detect the E6 gene sequences of HPV 6/11, 16 and 18. HPV was present in 20 of the cases (69%), HPV 6/11 in 14 (48%), HPV 16 in 19 (65%) and both HPV 6/11 and 16 in 13 of the specimens (45%). HPV 18 was not identified in any specimen. In all three of the squamous cell carcinomas based on inverted papillomas, HPV 6/11 and 16 were detected. These results were in agreement with other studies. While HPV is related etiologically to inverted papilloma, we suggest that HPV 16 may be involved in its malignant transformation.

Adult↗
PubMed1993

Structural and functional characterisation of recombinant human erythropoietin analogues.

Deletion mutants of a synthetic human erythropoietin-cDNA were transiently expressed in COS-7 cells and products analyzed using Western blots and a cell proliferation assay. Only two mutants with deletions affecting the N-terminal portion and the amino acid sequence 115-121 displayed biological activity. The exchange of hydrophilic, charged amino acids by alanine in two potential alpha-helical regions, the internal amino acid sequence 102-106 and the C-terminal sequence 154-159, causes a 2-11-fold loss of activity. The results suggest that both regions are involved in either maintaining the active structure of the hormone or interacting with the receptor.

Amino Acid Sequence↗
PubMed1993

Neonatal regional anesthesia: alternative to general anesthesia for urologic surgery.

The physiologic immaturity of respiratory musculature and central respiratory control centers leads to an increased risk of apnea and respiratory complications following general anesthesia in the neonate. Regional anesthetic techniques such as spinal and caudal epidural anesthesia may obviate the need for general anesthesia and lessen the risks of perioperative morbidity. Although these techniques have been previously described in infants, the majority of reports focus on regional anesthesia during herniorrhaphy in the former, preterm infant. There is relatively little or no information concerning regional anesthesia during urologic surgery in infants, especially during the actual neonatal period (0 to 28 days). We report on three neonates (2.17 to 3.8 kg) who required anesthetic care during the neonatal period for various urologic procedures including cystoscopy, incision of a ureterocele, and vesicostomy placement. Either caudal or spinal anesthesia was successfully used in the awake infant without the need for supplemental anesthetic agents (intravenous or inhalational). The advantages, risks, and applications of regional anesthesia during urologic surgery in the neonate are reviewed.

Anesthesia, Epidural↗
PubMed1993

Effects of rapid eye movement sleep deprivation on the properties of striatal dopaminergic system.

Using the water tank procedure, we have examined the effects of rapid eye movement (REM) sleep deprivation and associated stress on the properties of striatal dopaminergic system. While stress decreased the number of D1 and D2 dopamine receptors, a combination of REM sleep deprivation attenuated the decrease. The ratio of D1 to D2 densities, however, increased on both the stress and REM sleep deprivation groups. In contrast, the number of dopamine uptake sites remained unchanged. The enhanced behavioral responses to dopaminergic stimulants after REM sleep deprivation are discussed.

Animals↗