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Biomedical subjects

J Cartwright

Publications and source records attributed to J Cartwright.

At least 19 recordsLinked to original sources
PubMed2001

Early Oligocene initiation of North Atlantic Deep Water formation.

Dating the onset of deep-water flow between the Arctic and North Atlantic oceans is critical for modelling climate change in the Northern Hemisphere and for explaining changes in global ocean circulation throughout the Cenozoic era (from about 65 million years ago to the present). In the early Cenozoic era, exchange between these two ocean basins was inhibited by the Greenland-Scotland ridge, but a gateway through the Faeroe-Shetland basin has been hypothesized. Previous estimates of the date marking the onset of deep-water circulation through this basin-on the basis of circumstantial evidence from neighbouring basins-have been contradictory, ranging from about 35 to 15 million years ago. Here we describe the newly discovered Southeast Faeroes drift, which extends for 120 km parallel to the basin axis. The onset of deposition in this drift has been dated to the early Oligocene epoch ( approximately 35 million years ago) from a petroleum exploration borehole. We show that the drift was deposited under a southerly flow regime, and conclude that the initiation of deep-water circulation from the Norwegian Sea into the North Atlantic Ocean took place much earlier than is currently assumed in most numerical models of ancient ocean circulation.

Animals↗
PubMed2001

Affective-prosodic deficits in schizophrenia: comparison to patients with brain damage and relation to schizophrenic symptoms [corrected].

OBJECTIVE: Although affective prosody seems to be a dominant and lateralised communication function of the right hemisphere, focal lesions of either hemisphere may cause problems with its modulation. When impairment occurs after brain damage, the profiles of affective-prosodic disturbances differ depending on the hemisphere injured. Patients with left brain damage (LBD) improve their performance whereas patients with right brain damage (RBD) do not when the verbal-articulatory demands of the test stimuli are reduced systematically. One of the major arguments for a right hemispheric contribution to schizophrenia has been the documentation of affective prosodic deficits under the assumption that these abnormalities reflect right hemispheric dysfunction. Thus, an essential question to resolve is whether the profile of affective prosodic disturbances in schizophrenia is similar to LBD or RBD, or represents a unique variation. METHODS: Data were collected from four subject groups: 45 chronic, medication-stabilised, schizophrenic patients, 10 patients with focal LBD, nine patients with focal RBD, and 19 controls. All groups were tested on the aprosodia battery, which uses stimuli having incrementally reduced verbal-articulatory demands. Schizophrenic and aphasic symptoms were evaluated using standard assessment tools. RESULTS: For patients with impaired performance on the aprosodia battery, schizophrenic patients were statistically identical to patients with RBD and robustly different from those with LBD. Thirty eight schizophrenic patients (84.4%) were found to have some type of affective prosodic deficit with the predominant pattern indicating, at minimum, right posterior sylvian dysfunction (57.8%). When schizophrenic symptoms and aprosodic deficits were examined using a principal component analysis, affective comprehension and repetition loaded uniquely as separate factors. CONCLUSIONS: The profile of affective-prosodic deficits found in impaired schizophrenic patients is characteristic of RBD, supporting the concept that schizophrenia is a bihemispheric disease process. These deficits may also represent cardinal symptoms of schizophrenia as they are highly prevalent and, except for spontaneous affective prosody, are not associated statistically with traditional clusters of schizophrenic symptoms.

Adult↗
PubMed2000

Thin basement membrane disease with heavy proteinuria or nephrotic syndrome at presentation.

Thin basement membrane disease (TBMD) is a condition originally defined as diffuse thinning of the glomerular basement membrane (GBM) associated with hematuria in all patients. Although proteinuria has been described in up to 60% of patients with TBMD, it is almost always mild, with a 24-hour excretion mostly of less than 500 mg. We describe eight patients (four men and four women between 32 and 66 years of age) with TBMD who presented with heavy proteinuria or nephrotic syndrome. Among the seven cases with family history, hematuria was noted in five. All patients had a long history of microscopic hematuria, with episodic gross hematuria in two. Renal biopsies showed diffuse thinning of the GBM in each patient (mean between 185.3 x 29.8 nm and 232.6 x 34.5 nm versus control between 325 x 35 nm and 350 x 15 nm). Three cases showed thinning of GBM only (group I); the remaining five cases showed thinning of GBM associated with focal segmental glomerulosclerosis. All three patients of group I presented with nephrotic syndrome and normal renal function. Treatment with steroids resulted in remission of nephrotic syndrome in two, whereas nephrotic syndrome persisted in the untreated patient. Among the five patients in group II, nephrotic syndrome and normal renal function at presentation were noted in two, whereas the other three had heavy proteinuria (2.2, 2. 5, and 2.6 g/d, respectively) associated with mildly decreased renal function (serum creatinine 1.8, 1.3, and 1.5 mg/dL, respectively). At last follow-up, although the renal function was stable in all five, only the three who received steroid treatment had remission or marked improvement of proteinuria. Hematuria, however, persisted in all eight patients of both groups. Whether specific gene mutations are translated into structural changes responsible for both excessive GBM thinning and increased transcapillary permeability remains to be elucidated. Alternatively, the heavy proteinuria/nephrotic syndrome may not be related to TBMD, but rather is the manifestation of associated glomerular diseases. Follow-up, including a response to steroids, supports the latter hypothesis.

Adult↗
PubMed2000

Structure and function of the proteins of the mammalian Zona pellucida.

The zona pellucida (ZP) is the extracellular matrix that plays important roles in sperm-egg interaction. The ZP is composed of three major glycoproteins that exhibit heterogeneity due to extensive post-translational modifications including glycosylation and sulfation. Because of these modifications the nomenclature of ZP proteins from different species based on electrophoretic mobilities has been confusing. As the cDNAs and genes encoding the different ZP proteins have been isolated and sequenced, it is now possible to relate these ZP proteins according to gene families. Using the mouse ZP nomenclature, the ZP proteins from different mammalian species can be classified into three protein families: ZP1, ZP2, and ZP3. Although some of the structural domains of the ZP proteins of different species are conserved within each family, they exhibit distinct biological properties. In the mouse it has been established that ZP3 is the primary sperm receptor while ZP2 has secondary sperm receptor properties. In the pig, however, ZP1 has been shown to have sperm receptor activity similar to that observed in the rabbit and nonhuman primates. It is of interest that the human ZP2 and ZP3 gene families are 60-70% conserved with respect to the mouse ZP amino acid sequence, while the mouse ZP1 is only 39% conserved with respect to human ZP1. Such differences in protein structure and glysosylation may explain the marked species differences in the biochemical, physicochemical and immunochemical properties of the ZP. Studies have now shown that the proteins of the ZP are expressed in a stage specific manner and that there is increasing evidence that ZP proteins are expressed by both granulosa cells and the oocyte and may play a role in granulosa cell differentiation.

Animals↗
PubMed1997

Mucopolysaccharidosis presenting as pediatric multiple aortic aneurysm: first reported case.

Within the pediatric population, the rare aortic aneurysm is most often brought on by congenital cardiovascular malformation or connective tissue disorder, trauma, inflammatory disease, or infection. Thus our 8-year-old patient who had multiple aortic aneurysms and evidence of mucopolysaccharidosis presented a doubly unique case. Three and one-half months after the patient underwent emergency aortic valve replacement, we performed resection and graft replacement of both her descending thoracic aorta and thoracoabdominal aorta. Histologic analysis of the aneurysm wall displayed severe medial degeneration with large deposits of acid mucopolysaccharides. Subsequent evaluation, although negative for connective tissue disorders, showed glycosaminoglycans, chondroitin sulfate, and heparan sulfate in the patient's urine. These findings are diagnostic for a heterogeneous group of storage diseases termed mucopolysaccharidoses, although testing of the patient's cultured fibroblasts failed to reveal any specific previously described enzymatic defect. After reviewing the literature, we believe that this is the first known successfully treated pediatric aortic aneurysm associated with mucopolysaccharidosis.

Aorta↗
PubMed1997

Inhibitory effects of hypercholesterolemia and ox-LDL on angiogenesis-like endothelial growth in rabbit aortic explants. Essential role of basic fibroblast growth factor.

Hypercholesterolemic (HC) rabbits exhibit suppressed compensatory vascular growth after restriction of arterial supply. However, neovascularization is commonly found in atheromas containing inflammatory cells. We used an in vitro model to determine the effects of hypercholesterolemia on angiogenesis in the absence or presence of inflammatory cells. HC rabbit aortic explants (1 mm2) with or without (n = 90 each) lesion-forming inflammatory cells were cultured in a collagen matrix with serum-free medium. Explant-derived endothelial cell growth was organized into capillary-like microtubes (CLM) that could be videomicroscopically quantified. CLM growth from lesion-free HC explants was significantly reduced to 13 +/- 4% of the value in explants (n = 90) from normocholesterolemic (NC, n = 15) rabbits (P < .001). In contrast, in lesion-containing HC explants, the matrix was invaded by foam cells, and CLM growth was not inhibited. Immunoassayable basic fibroblast growth factor (bFGF, in pg/mL) in the culture medium was significantly lower in lesion-free HC (< 5) than NC explants (11 +/- 2, P < .01) or HC explants with lesions (14 +/- 3). In addition, CLM growth was reduced in NC explants incubated with oxidized LDL (ox-LDL, 50-100 micrograms/mL). Exogenous bFGF (10 ng/mL) reversed the inhibitory effects of hypercholesterolemia and ox-LDL, whereas bFGF-neutralizing antibody (10 micrograms/mL) abolished CLM growth in all groups. In cultured rabbit aortic endothelial cells, ox-LDL reduced DNA synthesis, but this inhibition was reversed by bFGF. We conclude that hypercholesterolemia and ox-LDL inhibit angiogenesis like endothelial growth because of a suppressed availability of endogenous bFGF. Retained responsiveness to exogenous bFGF suggests that inducing bFGF expression at targeted sites may improve collateral growth in hyperlipidemic arterial disease.

Animals↗
PubMed1997

Intraluminal crystalloids in breast carcinoma. Immunohistochemical, ultrastructural, and energy-dispersive x-ray element analysis in four cases.

OBJECTIVE: Intraluminal crystalloids have been described in the prostate, salivary gland, and ovary, but have not yet been reported in the breast. We report four cases of breast carcinoma in which these crystalloids were found in ducts with intraductal carcinoma or atypical hyperplasia. The presence of intraluminal crystalloids may be a useful adjunct in making a diagnosis of carcinoma or may be a feature to look for as a marker for the presence of carcinoma. DESIGN: Four cases of breast carcinoma containing intraluminal crystalloids were identified among 6900 surgical breast specimens between January 1990 and June 1995 at M. D. Anderson Cancer Center, Houston, Tex. Those sections with crystalloids identified by hematoxylin-eosin stain were stained with periodic acid-Schiff, Alcian blue, and mucicarmine stains. Immunohistochemical and ultrastructural studies and energy-dispersive x-ray analysis were also performed on these sections. RESULTS: The intraluminal crystalloids were eosinophilic, varied in shape and size, and did not exhibit birefringence under polarized light. Immunohistochemically, the crystalloids were negative for keratin, muscle-specific actin, and kappa and lambda light chains, but the surfaces stained positively for epithelial membrane antigen. By electron microscopy, the crystalloids had no limiting membrane and were composed of an electron-dense material with no discernible periodicity. By energy-dispersive x-ray element analysis, the crystalloids had no mineral content; however, sulfur was found, indicating a protein content. CONCLUSIONS: The pathogenesis and constituents of these intraluminal crystalloids remain to be determined. Inasmuch as intraluminal crystalloids have not been found in normal ducts or acini, or in ductal hyperplasia without atypia, their presence may serve as a marker for breast carcinoma.

Adult↗
PubMed1996

Neurodegeneration, myocardial injury, and perinatal death in mitochondrial superoxide dismutase-deficient mice.

Manganese superoxide dismutase (SOD2) converts superoxide to oxygen plus hydrogen peroxide and serves as the primary defense against mitochondrial superoxide. Impaired SOD2 activity in humans has been associated with several chronic diseases, including ovarian cancer and type I diabetes, and SOD2 overexpression appears to suppress malignancy in cultured cells. We have produced a line of SOD2 knockout mice (SOD2m1BCM/SOD2m1BCM) that survive up to 3 weeks of age and exhibit several novel pathologic phenotypes including severe anemia, degeneration of neurons in the basal ganglia and brainstem, and progressive motor disturbances characterized by weakness, rapid fatigue, and circling behavior. In addition, SOD2m1BCM/SOD2m1BCM mice older than 7 days exhibit extensive mitochondrial injury within degenerating neurons and cardiac myocytes. Approximately 10% of SOD2m1BCM/SOD2m1BCM mice exhibit markedly enlarged and dilated hearts. These observations indicate that SOD2 deficiency causes increased susceptibility to oxidative mitochondrial injury in central nervous system neurons, cardiac myocytes, and other metabolically active tissues after postnatal exposure to ambient oxygen concentrations. Our SOD2-deficient mice differ from a recently described model in which homozygotes die within the first 5 days of life with severe cardiomyopathy and do not exhibit motor disturbances, central nervous system injury, or ultrastructural evidence of mitochondrial injury.

Animals↗
PubMed1996

An assessment of the routes of incorporation of opiates into beard hair after a single oral dose of codeine.

The time course of appearance of immunoreactive opiates was monitored in saliva, sweat, and beard hair in six healthy whites who were not opiate users after oral administration of 60 mg of codeine phosphate. The opiate concentration in saliva peaked within 30 min of drug administration and returned to near the predose level within 24 h. Ninety-one percent of the total secretion of opiates in sweat was collected by the skin-collection patch worn during the first 24 h after drug administration. Detectable material was also present in sweat patches on the following 2 days. Opiates were detected in extracts of alkali digests of beard hair in all subjects on the day after drug administration. Hair concentration peaked on day 3 after dosing and then decreased continuously until day 8. From day 8 until the end of the experiment on day 14, beard hair contained opiate concentrations significantly greater than the predose level. From comparison with cotinine pharmacokinetics, it is proposed that an early and the largest transfer of opiates into beard hair is through sweat. Transfer during hair growth is secondary and of comparable importance to a newly identified contribution of long duration that may involve transfer from storage depots within skin.

Adult↗
PubMed1995

Disruption of the adenosine deaminase gene causes hepatocellular impairment and perinatal lethality in mice.

We have generated mice with a null mutation at the Ada locus, which encodes the purine catabolic enzyme adenosine deaminase (ADA, EC 3.5.4.4). ADA-deficient fetuses exhibited hepatocellular impairment and died perinatally. Their lymphoid tissues were not largely affected. Accumulation of ADA substrates was detectable in ADA-deficient conceptuses as early as 12.5 days postcoitum, dramatically increasing during late in utero development, and is the likely cause of liver damage and fetal death. The results presented here demonstrate that ADA is important for the homeostatic maintenance of purines in mice.

Adenosine Deaminase↗
PubMed1995

Pelvic lymph node histiocytosis mimicking metastatic prostatic adenocarcinoma: association with hip prostheses.

PURPOSE: Histological changes in lymph nodes simulating metastatic prostatic adenocarcinoma are reported. MATERIALS AND METHODS: Lymph node frozen sections from 3 patients with prostatic cancer displayed marked histiocytosis. This tissue was subjected to histochemical, immunohistochemical and electron microscopic studies. RESULTS: Only 1 erroneous diagnosis of metastasis was made. All patients had hip prostheses for at least 6 years. Tissue replacing up to 80% of lymph nodes consisted of histiocytes containing large amounts of polyethylene. CONCLUSIONS: Hip replacement predisposes the patient to have pelvic lymph node histiocytosis mimicking metastatic adenocarcinoma. This history should be communicated to the pathologist. Polyethylene is the most important factor in the cause of post-prosthesis lymph node histiocytosis.

Adenocarcinoma↗