Marine and estuarine toxicology and chemistry.
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Seawater↗
Biomedical subjects
G Scott
Publications and source records attributed to G Scott.
Septo-optic dysplasia and unexpected adult death--an autopsy approach.
A 20-year-old woman who suffered from septo-optic dysplasia died unexpectedly following a presumed viral gastroenteritis. Autopsy and neuropathological examination confirmed optic nerve hypoplasia with absence of the septum pellucidum. Marked adrenal gland hypoplasia reflected hypothalamic hypopituitarism. The small and large intestines were dilated and filled with liquid fecal material. This case demonstrates that individuals with septo-optic dysplasia may be at risk of unexpected death at all ages. The complexity of mechanisms of death in rare dysmorphic conditions may be overlooked if relevant clinical information is not available at the time of autopsy and unless specific steps are taken to clearly delineate the underlying features of the condition.
Adrenal Gland Diseases↗
The outcome of cemented vs. cementless fixation of a femoral component in total knee replacement (TKR) with the identification of radiological signs for the prediction of failure.
A survival analysis and radiological review were performed on a series of femoral total knee arthroplasty (TKA) prostheses either cemented (150 cases) or cementless, press-fit (201 cases). The internal surface of the femoral components were shot-blast CoCr alloy. The incidence of loosening of the femoral component at 6 years was 9.8% with cementless fixation and 0.6% with cement (P<0.05) at 6 years. Amongst uncemented prostheses, there was no difference in the survival or radiological outcome with the use of a stem as against two condylar pegs. The clinical need for revision may be predicted radiologically 3 years after operation in symptomless patients by noting a change in component position combined with progressive radiolucent lines and osteolysis. Thus, radiological follow-up should be continued for a minimum of 3 years after knee replacement. The use of a stem enabled the detection of radiolucent lines which we believe were missed around prostheses with condylar pegs. Thus, the use of a stem improves the prediction of failure (but does not improve fixation).
Journal Article↗
Preferential oxidation of zinc finger 2 in estrogen receptor DNA-binding domain prevents dimerization and, hence, DNA binding.
For approximately one-third of estrogen receptor (ER)-positive breast cancer patients, extracted tumor ER is unable to bind to its cognate DNA estrogen response element (ERE), an effect that is partly reversible by the thiol-reducing agent dithiothreitol (DTT). Full-length (67 kDa) ER or its 11 kDa recombinant DNA-binding domain (ER-DBD) is also susceptible to loss of structure and function by the action of oxidants such as diamide and hydrogen peroxide; however, prior DNA binding by ER or ER-DBD protects against this oxidant induced loss of function. The ER-DBD contains two (Cys)(4)-liganded zinc finger motifs that cooperate to stabilize a rigid DNA-binding recognition helix and a flexible helix-supported dimerization loop, respectively. Comparisons between synthetic peptide analogues of each zinc finger and recombinant ER-DBD in the presence of zinc by electrophoretic mobility shift assay, circular dichroism, and mass spectrometry confirm that cooperativity between these zinc fingers is required for both ER-DBD structure (alpha-helicity) and function (dimeric DNA binding). Rapid proteolytic digestion of monomeric, non-DNA-bound ER-DBD followed by HPLC-MS analysis of the resulting peptides demonstrates that zinc inhibits thiol oxidation of the DNA-binding finger, but not the finger supporting the flexible dimerization loop, which remains sensitive to internal disulfide formation. These findings indicate that the loss of ER DNA-binding function in extracts from some primary breast tumors and in ER or ER-DBD exposed to thiol-reacting oxidants results from this asymmetric zinc finger susceptibility to disulfide formation that prevents dimerization. Although ER-DBD contains several strategically located methionine residues, they are less susceptible to oxidation than the thiol groups and, thus, afford no protection against cysteine oxidation and consequent loss of ER DNA-binding function.
Amino Acid Sequence↗
Risk factors for preterm birth, low birth weight, and intrauterine growth retardation in infants born to HIV-infected pregnant women receiving zidovudine. Pediatric AIDS Clinical Trials Group 185 Team.
OBJECTIVE: To evaluate independent contributions of maternal factors to adverse pregnancy outcomes (APO) in HIV-infected women receiving antiretroviral therapy (ART). DESIGN: Risk factors for preterm birth (< 37 weeks gestation), low birth weight (LBW) (< 2500 g), and intrauterine growth retardation (IUGR) (birth weight < 10th percentile for gestational age) examined in 497 HIV-infected pregnant women enrolled in PACTG 185, a perinatal clinical trial. METHODS: HIV RNA copy number, culture titer, and CD4 lymphocyte counts were measured during pregnancy. Information collected included antenatal use of cigarettes, alcohol, illicit drugs; ART; obstetric history and complications. RESULTS: Eighty-six percent were minority race/ethnicity; 86% received antenatal monotherapy, predominantly zidovudine (ZDV), and 14% received combination antiretrovirals. Preterm birth occurred in 17%, LBW in 13%, IUGR in 6%. Risk of preterm birth was independently associated with prior preterm birth [odds ratio (OR) 3.34; P < 0.001], multiple gestation (OR, 6.02; P = 0.011), antenatal alcohol use (OR, 1.91; P = 0.038), and antenatal diagnosis of genital herpes (OR, 0.24; P = 0.022) or pre-eclampsia (OR, 6.36; P = 0.025). LBW was associated with antenatal diagnosis of genital herpes (OR, 0.08; P = 0.014) and pre-eclampsia (OR, 5.25; P = 0.049), and baseline HIV culture titer (OR, 1.41; P = 0.037). IUGR was associated with multiple gestation (OR, 8.20; P = 0.010), antenatal cigarette use (OR, 3.60; P = 0.008), and pre-eclampsia (OR, 12.90; P = 0.007). Maternal immune status and HIV RNA copy number were not associated with APO. CONCLUSIONS: Risk factors for APO in antiretroviral treated HIV-infected women are similar to those reported for uninfected women. These data suggest that provision of prenatal care and ART may reduce APO.
Adult↗
Check, check, and check again
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Journal Article↗
Topography and severity of axonal injury in human spinal cord trauma using amyloid precursor protein as a marker of axonal injury.
STUDY DESIGN: Axonal injury was examined in 18 human cases of acute spinal cord compression using amyloid precursor protein as a marker of AI. OBJECTIVES: To topographically map and semiquantitate axonal injury in spinal cord compression of sufficient severity to produce para- or quadriplegia. SUMMARY OF BACKGROUND DATA: Amyloid precursor protein is carried along the axon by fast axoplasmic transport and has been extensively used as a marker of traumatic axonal injury. METHODS: The study group comprised 18 cases of spinal cord compression (17 due to fracture dislocation of the vertebral column and 1 iatrogenic compression from Harrington rods) and two normal control. All the cords were examined according to a standard protocol, and at least 10 segmental levels were immunostained using a monoclonal antibody to amyloid precursor protein and immunopositive AI was semiquantitated using a grading system to provide the axonal injury severity score (AISS). The focal injury at the site of cord compression (haemorrhage, haemorrhagic necrosis, ischaemic necrosis) was also semiquantitated to provide the focal injury area score (FIAS). AI occurring around the site of focal compression (focal axonal injury severity score or FAISS) was distinguished from AI distant to the focal injury (nonfocal axonal injury severity score or NFAISS). RESULTS: All 18 cases showed widespread amyloid precursor protein immunoreactive axonal injury and the AISS ranged from 28 to 60%. In all cases, the FAISS was greater than the NFAISS and there was a statistically significant relationship between the AISS and the FIAS. CONCLUSION: Acute spinal cord compression of sufficient severity to produce permanent paralysis causes widespread axonal damage that is maximal at the site of compression but also present throughout the length of the cord in segments far distant from the site of the focal injury.
Adolescent↗
Cervical and thoracic juxtafacet cysts causing neurologic deficits.
STUDY DESIGN: Case reports and review of the literature. OBJECTIVES: To review the clinical features, treatment, and outcome of juxtafacet cysts. SUMMARY OF BACKGROUND DATA: There have previously been 4 reported cases of thoracic juxtafacet cysts and 19 cases of cervical juxtafacet cysts. Cervical cysts have usually originated from the cruciate ligament and caused myelopathy. Thoracic cysts are usually signaled by myelopathy. METHODS: The records of the Neurosurgery Department of Royal Adelaide Hospital from 1980 through 1995 were reviewed for cases of intraspinal juxtafacet cysts. RESULTS: Eight cases of intraspinal juxtafacet cysts were identified; six were in the lumbar spine. One patient had a cervical cyst related to a facet joint and had unilateral radiculopathy. A second patient with a thoracic cyst had the gradual onset of myelopathy. Both patients had surgical excision of the cyst without resection of the adherent dura. The symptoms and neurologic signs improved in each case. CONCLUSIONS: Cervical and thoracic juxtafacet cysts are rare lesions that are usually signaled by myelopathy. Results of surgery are excellent in most cases, even if the cyst is not completely excised.
Aged↗
Minocycline-induced hyperpigmentation in patients with pemphigus and pemphigoid.
BACKGROUND: Immunosuppressive medications typically used to treat the immunobullous disorders pemphigus vulgaris, pemphigus foliaceous, and bullous pemphigoid can have serious adverse effects. The tetracycline family of antibiotic drugs has been shown to be effective in the treatment of these conditions with a more favorable side effect profile. Minocycline hydrochloride use has been associated with various forms of hyperpigmentation, and its incidence is well reported in acne vulgaris and rheumatoid arthritis. We examined a series of 9 patients treated with minocycline for pemphigus or pemphigoid, most of whom have developed cutaneous hyperpigmentation. OBSERVATIONS: Seven of 9 patients treated with minocycline, 50 mg daily (1 patient) or 100 mg twice daily (8 patients), for pemphigus vulgaris, pemphigus foliaceous, or bullous pemphigoid developed hyperpigmentation, which necessitated discontinuing therapy. Five of these patients had experienced notable clinical improvement of their immunobullous disease with minocycline therapy. The average duration of treatment was 8.2 months (range, 1-25 months). The second most common adverse effect in our group was oral candidiasis, which occurred in 2 patients. CONCLUSIONS: We found a favorable response to minocycline therapy in 5 of 9 patients. However, 7 patients developed localized hyperpigmentation as early as 1 month after starting medication use. This incidence of minocycline-induced hyperpigmentation is significantly higher in immunobullous disease than in acne vulgaris or rheumatoid arthritis. This increased incidence may be related to an increase in pigment deposition complexed with collagen during the remodeling process, subclinical inflammation, or glucocorticosteroid-induced skin fragility. The hyperpigmentation process was reversible, as most of our patients had fading of their pigmentation after minocycline cessation.
Adult↗
Prevention and control of infections in intensive care.
Small intensive care units (ICUs) functioning within their capacity and caring mainly for post-operative patients have fewer problems with infection control than larger ICUs with a varied case mix, sub-optimal staffing levels, and high levels of antibiotic consumption. Under these circumstances chronic cross colonisation and infection are inevitable and outbreaks may occur. Little can be done to reduce the risks of infection which arise as a direct result of the patient's clinical condition and prior colonisation status. However, selection pressure from antibiotic usage can be modified, as can environmental hygiene, ventilation and architectural design. One of the simplest measures for reducing cross infection remains one of the most intractable: compliance by staff with protocols and standards for maintaining hand hygiene. Simplification of procedures by the ready availability of alcohol hand rub preparations with or without chlorhexidine may improve matters.
Anti-Bacterial Agents↗
Analysis of single-nucleotide polymorphisms in the interleukin-4 receptor gene for association with inflammatory bowel disease.
Genetic linkage analysis in families with multiple cases of inflammatory bowel disease (IBD) has mapped a gene which confers susceptibility to IBD to the pericentromeric region of chromosome 16 (IBD1). The linked region includes the interleukin(IL)-4 receptor gene (IL4R). Since IL-4 regulation and expression are abnormal in IBD, the IL4R gene is thus both a positional and functional candidate for IBD1. We screened the gene for single-nucleotide polymorphisms (SNPs) by fluorescent chemical cleavage analysis, and tested a subset of known and novel SNPs for allelic association with IBD in 355 families, which included 435 cases of Crohn's disease and 329 cases of ulcerative colitis. No association was observed between a haplotype of four SNPs (val50ile, gln576arg, A3044G, G3289A) and either the Crohn's disease or ulcerative colitis phenotypes using the transmission disequilibrium test. There was also no evidence for association when the four markers were analyzed individually. The results indicate that these variants are not significant genetic determinants of IBD, and that the IL4R gene is unlikely to be IBD1. Linkage disequilibrium analyses showed that the val50ile and gln576arg variants are in complete equilibrium with each other, although they are separated by only about 21 kilobases of genomic DNA. This suggests that a very dense SNP map may be required to exclude or detect disease associations with some candidate genes.
Alleles↗
The human polo-like kinase, PLK, regulates cdc2/cyclin B through phosphorylation and activation of the cdc25C phosphatase.
Entry into mitosis by mammalian cells is triggered by the activation of the cdc2/cyclin B holoenzyme. This is accomplished by the specific dephosphorylation of key residues by the cdc25C phosphatase. The polo-like kinases are a family of serine/threonine kinases which are also implicated in the control of mitotic events, but their exact regulatory mechanism is not known. Recently, a Xenopus homologue, PLX1, was reported to phosphorylate and activate cdc25, leading to activation of cdc2/cyclin B. Jurkat T leukemia cells were chemically arrested and used to verify that PLK protein expression and its phosphorylation state is regulated with respect to cell cycle phase (i.e., protein is undetectable at G1/S, accumulates at S phase and is modified at G2/M). Herein, we show for the first time that endogenous human PLK protein immunoprecipitated from the G2/M-arrested Jurkat cells directly phosphorylates human cdc25C. In addition, we demonstrate that recombinant human (rh) PLK also phosphorylates rhcdc25C in a time- and concentration-dependent manner. Phosphorylation of endogenous cdc25C and recombinant cdc25C by PLK resulted in the activation of the phosphatase as assessed by dephosphorylation of cdc2/cyclin B. These data are the first to demonstrate that human PLK is capable of phosphorylating and positively regulating human cdc25C activity, allowing cdc25C to dephosphorylate inactive cdc2/cyclin B. As this event is required for cell cycle progression, we define at least one key regulatory mode of action for human PLK in the initiation of mitosis.
CDC2 Protein Kinase↗
The yeast p53 functional assay: a new tool for molecular epidemiology. Hopes and facts.
The assumption of molecular epidemiology that carcinogens leave fingerprints has suggested that analysis of the frequency, type, and site of mutations in genes frequently altered in carcinogenesis may provide clues to the identification of the factors contributing to carcinogenesis. In this mini-review, we revise the development, and validation of the yeast-based p53 functional assay as a new tool for molecular epidemiology. We show that this assay has some very interesting virtues but also has some drawbacks. The yeast functional assay can be used to determine highly specific mutation fingerprints in the human p53 cDNA sequence. Discrimination is possible when comparing mutation spectra induced by sufficiently different mutagens. However, we also reported that the same carcinogen may induce distinguishable mutation spectra due to known influencing factors.
Alkylating Agents↗
Angiocentric primary cutaneous T-cell-rich B-cell lymphoma: a case report and review of the literature.
BACKGROUND: T-cell-rich B-cell lymphoma (TCRBCL) is an uncommon B-cell lymphoma, which is characterized histologically by a small number of neoplastic B cells surrounded by large numbers of nonneoplastic T cells. Diagnosis is frequently difficult because the neoplastic 'B-cell population may be quite sparse, and immunohistochemical and molecular analysis to identify the B-cell origin and clonality of the cells is necessary. METHODS: In this report we present an additional case of primary cutaneous TCRBCL with immunohistochemical and gene rearrangement studies and review the literature of this unusual entity. RESULTS: The patient was a 52-year-old woman who had a slowly growing cutaneous lymphoma which fulfills the strictest criteria initially proposed for a diagnosis of TCRBCL. This case has additional features of a prominent angiocentric/angioinvasive histology and dual clonality, showing both immunoglobulin heavy chain and T-cell receptor gene rearrangements. CONCLUSIONS: Controversy surrounds the notion of TCRBCL as a distinct clinicopathological entity. There have only been 14 reported cases of TCRBCL with skin involvement in the literature and only seven of these cases have arisen in the skin. To better understand the histological and clinical characterisitcs of TCRBCL we have reviewed previously reported cases of TCRBCL with skin involvement, and contrast them with the present case.
Blood Vessels↗
Hot spot mutations in keratin 2e suggest a correlation between genotype and phenotype in patients with ichthyosis bullosa of Siemens.
Ichthyosis bullosa of Siemens (IBS) is a rare disorder of cornification characterized by blister formation in the upper suprabasal layers of the epidermis. Molecular analysis of IBS has identified mutations in the keratin 2e (K2e) gene, which is located in the type II keratin gene cluster on chromosome 12q. We have studied two IBS families and have identified heterozygous point mutations in codon 493 of the K2e gene in both families. Whereas a non-conservative amino acid substitution at position 117 of the 2B region of K2e (E117K) was associated with a severe phenotype in family 1, family 2 showed mild clinical features as a result of a conservative substitution (E117D). These data suggest a phenotype-genotype correlation in these families.
Adult↗
A prospective comparison of three heat preservation methods for patients undergoing hypothermic cardiopulmonary bypass.
OBJECTIVE: To prospectively compare 3 methods of body heat preservation in patients undergoing surgery requiring the use of hypothermic cardiopulmonary bypass (CPB). DESIGN: Prospective, randomized, and nonblinded. SETTING: University teaching hospital. PARTICIPANTS: Adult cardiac surgery patients (n = 101). INTERVENTIONS: Subjects were randomly assigned to 1 of 3 treatment groups: Group 1 (n = 33) used a fluid-filled warming blanket, group 2 (n = 31) used a heated and humidified breathing circuit, and group 3 (n = 37) used intravenous fluid warmers for the administration of all fluids. Treatments started on separation from CPB and concluded at the end of the intraoperative experience. Anesthetic technique, minute ventilation, conduct of CPB, and room temperature in the operating room were standardized. MEASUREMENTS AND MAIN RESULTS: Blood temperature was measured at its nadir on CPB, on separation from CPB, and just before departure from the operating room. No differences were found among groups for CPB duration, coldest venous temperature on CPB, rewarming time, rate of rewarming, room temperature, or blood temperature on separation from CPB. There were no significant differences found in post-CPB temperature afterdrop among groups. CONCLUSIONS: This study suggests that there is no statistically significant disparity in the effectiveness of these 3 intraoperative heat preservation methods. Ease of use and cost-effectiveness should guide the choice of warming method post-CPB.
Adult↗
Test and teach. Number Ninety Seven. Granulomatous inflammation and CNS germinoma.
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Adolescent↗
Inclusion body myositis associated with systemic lupus erythematosus (SLE)
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Adult↗