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Biomedical subjects

E Gonzalez

Publications and source records attributed to E Gonzalez.

At least 55 records · Page 3Linked to original sources
PubMed2000

Low cleavage activity of 15,15'dioxygenase to convert beta-carotene to retinal in cattle compared with goats, is associated with the yellow pigmentation of adipose tissue.

Two experiments (one with twelve heifers and the other with 14 goats) were designed to evaluate the effect of increasing dietary beta-carotene concentration on the activity of the cleaving enzyme 15,15' beta-carotene dioxygenase and the concentration of beta-carotene and retinol in selected tissues. The experiments lasted 120 days. During the first 90 days animals were offered a beta-carotene unsupplemented diet. In the following 30 days, they were distributed to one of three treatments: 0, 5.5 or 352 mg of beta-carotene/kg of dry matter intake. All animals were slaughtered at the end. In heifers the concentration of beta-carotene in plasma, reflected the level of beta-carotene fed. Goats had detectable levels of beta-carotene only on day 10 of supplementation. In the liver, beta-carotene concentrations were highest with the 352 dose in both species. Heifers had the highest concentration of beta-carotene in the adipose tissue. In bovines, no interaction between beta-carotene treatment and intestinal sampling site was found (P > 0.2) for the activity of 15,15 dioxygenase. Across beta-carotene levels, results of the enzyme assay were: 0.19, 0.32 and 0.45 nmol retinal/(mg S-9 protein/h) (P < 0.01) for 0, 5.5 and 352 mg beta-carotene.kg dry matter intake -1.d-1, respectively; across intestinal sampling sites results of the enzyme assay were 0.45, 0.43 and 0.08 nmol retinal/(mg S-9 protein/h) (P < 0.01) for duodenum, jejunum and ileum, respectively. Caprine data showed an interaction between beta-carotene treatment and intestinal sampling site (P < 0.05) for the activity of 15,15 dioxygenase. The results for treatment 0 were: 1.4, 1.4 and 0; for treatment 5.5: 1.41, 1.42 and 0.13; and for treatment 352: 1.46, 1.99 and 0.48 nmol retinal/mg S-9 protein/h for duodenum, jejunum and ileum, respectively. The lower levels of duodenal and jejunal 15,15'dioxygenase activity in cattle compared with goats, may explain the greater pigmentation of adipose tissue in the former ruminant specie.

Adipose Tissue↗
PubMed2000

Roux-en-Y venting jejunostomy in pancreatic transplantation: a novel approach to monitor rejection and prevent anastomotic leak.

INTRODUCTION: Pancreatic transplantation (PTx) with portal venous delivery of insulin and enteric drainage of the exocrine secretion is more physiologic than bladder-systemic (BS) drainage. With portal-enteric (PE) PTx, the diagnosis of acute rejection (AR) requires a percutaneous biopsy. The roux-en-y (RNY) venting jejunostomy in patients with PEPTx offers a novel approach to monitor rejection and prevent anastomatic leaks. METHODS: From January 1996 to December 1998, we performed 17 simultaneous kidney/pancreas transplants (SKPTx). The initial 4 patients underwent BS drainage and the subsequent 13 patients underwent RNY venting jejunostomy with PE drainage. All patients were treated with quadruple therapy. There were 9 males, 14 patients were Caucasian with a mean age of 32 yr (range 30-54 yr), and a mean pre-transplantation duration of diabetes of 25 yr. Six patients underwent endoscopic donor duodenal biopsy through the jejunostomy to rule out clinically suspected AR. Gastrograffin was inserted into the jejunostomy to examine the integrity of anastamosis when indicated. In 9 out of 13 patients, the venting jejunostomy was taken down 9-12 months post-transplantation after allograft function was stable. RESULTS: Actual patient, kidney, and pancreas graft survival rates were 100, 100 and 94%, respectively, after a mean follow-up of 16 months. Renal allografts functioned immediately in 89% of patients. The mean length of hospital stay was 19 d. Four (23%) patients (2 with BS drainage and 2 with PE drainage) suffered an AR episode in the first month, and 4 (23%) patients had five AR from 3-36 months post-transplantation. Other complications were post-operative bleeding in 3 patients, wound infection in 2 patients and a proximal duodenal stump leak in 1 patient. In patients with clinical rejection, endoscopy through the venting jejunostomy showed inflamed, friable doudenal mucosa and doudenal biopsy findings were compatible with AR. CONCLUSION: These preliminary results suggest that RNY venting jejunostomy with PE drainage can be used safely to diagnose and monitor pancreas AR and to diagnose and prevent anastamotic leaks. This technique will be even more useful to visualize transplanted duodenal mucosa, collect pancreatic secretions (amylase) for analysis and perform endoscopic retrograde cholangiopancreatography if needed to obtain pancreatic biopsies.

Adult↗
PubMed2000

The HOS test and its relationship to fertility in the stallion.

The hypo-osmotic test has been used successfully on equine semen and was considered to be a simple and accessible method which could be a useful addition to routine equine semen analysis. It was therefore of interest to determine whether the hypo-osmotic test is significantly correlated to proposed criteria of fertility. The stallions were divided into two groups on the basis of threshold levels of fertility. A significant difference (P<0.05) was found between the two groups for the following parameters: progressive motility, morphologically normal spermatozoa, percentage of swelling with the hypo-osmotic test, percentage of pregnant mares and number of services per pregnancy. The hypo-osmotic test provided a simple evaluation of membrane function and the results obtained show stallions with low swelling scores (<40%) to be of doubtful fertility. The hypo-osmotic test was not correlated with percentage of pregnant mares but showed a tendency to correlate with the number of services per pregnancy, therefore it could be an additional method for evaluating stallion fertility. Further studies are needed to confirm this observation.

Animals↗
PubMed2000

Intraoperative electromyography of the superior gluteal nerve during lateral approach to the hip for arthroplasty: a prospective study of 12 patients.

The purpose of this study was to evaluate the incidence of intraoperative superior gluteal nerve irritation and to identify specific surgical maneuvers that may harm the nerve. Continuous intraoperative electromyography (EMG) monitoring of the superior gluteal nerve-innervated muscles (gluteus medius and tensor fascia lata muscles) was performed in 12 patients undergoing total hip arthroplasty. A modified lateral approach was used, including a partial anterior osteotomy of the greater trochanter with splitting of the gluteus medius and vastus lateralis muscles. All patients had a clinical follow-up examination 1 year postoperatively to evaluate abductor muscle function. Irritation of the nerve occurred first during splitting of the gluteus medius muscle, then with increased gluteus medius retraction for exposure of the acetabulum, and finally during positioning of the leg for preparation of the femur. The detected EMG alterations were important because they were found in a single patient with persistent abductor muscle weakness.

Aged↗
PubMed2000

Synovial chondromatosis of the temporomandibular joint with intracranial extension.

We present a rare case of synovial chondromatosis of the left temporomandibular joint with intracranial extension and review the relevant literature. This is the sixth published report of such a skull base tumour. We discuss imaging characteristics and the differential diagnosis with regards to a curative surgical resection.

Chondromatosis, Synovial↗
PubMed2000

Rapidly progressing mycosis fungoides presenting as follicular mucinosis.

Follicular mucinosis can occur as a primary idiopathic disorder or can arise in association with benign or malignant disease, most notably mycosis fungoides. We describe a patient with an aggressive folliculotropic variant of mycosis fungoides that initially presented as follicular mucinosis with alopecia. One month after the diagnosis of follicular mucinosis, a diagnosis of mycosis fungoides was made, and 3 months later inguinal lymph node involvement with mycosis fungoides developed. A skin biopsy specimen demonstrated prominent follicular mucinosis with folliculotropism of atypical cells and intrafollicular Pautrier's microabscesses. As demonstrated in this case, follicular mucinosis can be a presenting sign of rapidly progressive mycosis fungoides. In our review of follicular mucinosis and its association with mycosis fungoides, we found that the folliculotropic variant of mycosis fungoides appears more commonly to have an aggressive course than classic mycosis fungoides.

Adult↗
PubMed2000

The homeobox gene bozozok promotes anterior neuroectoderm formation in zebrafish through negative regulation of BMP2/4 and Wnt pathways.

The neuroectoderm of the vertebrate gastrula was proposed by Nieuwkoop to be regionalized into forebrain, midbrain, hindbrain and spinal cord by a two-step process. In the activation step, the Spemann gastrula organizer induces neuroectoderm with anterior character, followed by posteriorization by a transforming signal. Recently, simultaneous inhibition of BMP and Wnt signaling was shown to induce head formation in frog embryos. However, how the inhibition of BMP and Wnt signaling pathways specify a properly patterned head, and how they are regulated in vivo, is not understood. Here we demonstrate that the loss of anterior neural fates observed in zebrafish bozozok (boz) mutants occurs during gastrulation due to a reduction and subsequent posteriorization of neuroectoderm. The neural induction defect was correlated with decreased chordino expression and consequent increases in bmp2b/4 expression, and was suppressed by overexpression of BMP antagonists. Whereas expression of anterior neural markers was restored by ectopic BMP inhibition in early boz gastrulae, it was not maintained during later gastrulation. The posteriorization of neuroectoderm in boz was correlated with ectopic dorsal wnt8 expression. Overexpression of a Wnt antagonist rescued formation of the organizer and anterior neural fates in boz mutants. We propose that boz specifies formation of anterior neuroectoderm by regulating BMP and Wnt pathways in a fashion consistent with Nieuwkoop's two-step neural patterning model. boz promotes neural induction by positively regulating organizer-derived chordino and limiting the antineuralizing activity of BMP2b/4 morphogens. In addition, by negative regulation of Wnt signaling, boz promotes organizer formation and limits posteriorization of neuroectoderm in the late gastrula.

Animals↗
PubMed1999

Race-specific HIV-1 disease-modifying effects associated with CCR5 haplotypes.

Genetic variation in CC chemokine receptor 5 (CCR5), the major HIV-1 coreceptor, has been shown to influence HIV-1 transmission and disease progression. However, it is generally assumed that the same CCR5 genotype (or haplotype) has similar phenotypic effects in different populations. To test this assumption, we used an evolutionary-based classification of CCR5 haplotypes to determine their associated HIV-1 disease-modifying effects in a large well-characterized racially mixed cohort of HIV-1-seropositive individuals. We demonstrate that the spectrum of CCR5 haplotypes associated with disease acceleration or retardation differs between African Americans and Caucasians. Also, we show that there is a strong interactive effect between CCR5 haplotypes with different evolutionary histories. The striking population-specific phenotypic effects associated with CCR5 haplotypes emphasize the importance of understanding the evolutionary context in which disease susceptibility genes are expressed.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Teledermatology in a capitated delivery system using distributed information architecture: design and development.

OBJECTIVE: This report describes the design, development, and technical evaluation of a teledermatology system utilizing digital images and electronic forms captured through, stored on, and viewed through a common web server in an urban capitated delivery system. MATERIALS AND METHODS: The authors designed a system whereby a primary care physician was able to seek a dermatologic consultation electronically, provide the specialist with digital images acquired according to a standardized protocol, and review the specialist response within 2 business days of the request. The settings were two primary care practices in eastern Massachusetts that were affiliated with a large integrated delivery system. Technical evaluation of the effectiveness of the system involved 18 patients. Main outcome measures included physician and patient satisfaction and comfort and efficiency of care delivery. RESULTS: In 15 cases, the consultant dermatologist was comfortable in providing definitive diagnosis and treatment recommendations. In 3 cases, additional information (laboratory studies or more history) was requested. There were no instances where the dermatologist felt that a face-to-face visit was necessary. CONCLUSIONS: This novel approach shows promise for the delivery of specialist expertise via the internet. Cost-effectiveness studies may be necessary for more widespread implementation.

Computer Systems↗
PubMed1999

Prostate cancer screening in primary care.

BACKGROUND: Little is known about the actual frequency with which men have prostate screening in primary care settings, nor are the determinants of screening understood. METHODS: We examined the records of 50 consecutive primary care office visits by men aged 50 or older. Men were asked to complete a brief questionnaire outlining their previous use of prostate screening services and the factors that influenced screening. RESULTS: Screening in the previous year with digital rectal examination (DRE) and prostate specific antigen (PSA) was reported by 46% and 30% of respondents, respectively. Most respondents (86%) had heard of prostate screening and most (78%) believed it was effective. The only factor predictive of screening with DRE in multivariate analysis was a doctor's discussion of screening (odds ratio, 4.8). Two factors were predictive of PSA screening--knowing someone who had prostate cancer (odds ratio, 12.8) and advancing age (odds ratio [per year], 1.1). CONCLUSIONS: Many men are not having annual prostate screening. Men who were older, who reported knowing someone with prostate cancer, and whose doctors discussed screening, were more likely to have been screened in the past year.

Attitude to Health↗
PubMed1999

Chlorzoxazone, a selective probe for phenotyping CYP2E1 in humans.

The ability of human cytochromes P450 other than CYP2E1 to catalyse the 6-hydroxylation of chlorzoxazone (6-OH-CHZ) was examined in vitro using human liver microsomal preparations and in vivo using chlorzoxazone as a metabolic probe. Chlorzoxazone 6-hydroxylation activity was significantly correlated with 4-nitrophenol 2-hydroxylase activity and immunodetected CYP2E1 in 14 human liver samples (r = 0.92 and 0.81, P < 0.001, respectively). Conversely, this catalytic activity was not correlated with CYP 3A or CYP1A activities. Diethyldithiocarbamate (DEDTC), a specific CYP2E1 inhibitor, reduced chlorzoxazone 6-hydroxylase activity by 92.3 +/- 7.6% (n = 14 samples) while ketoconazole, a specific CYP3A inhibitor, reduced this activity by 8.6 +/- 6.3% (n = 14). The residual activity following preincubation with DEDTC was significantly correlated with nifedipine oxidation and tamoxifen N-demethylations, both specific to CYP3A (r = 0.76 and 0.68, respectively). Genetically produced pure human CYP2E1 and 3A4 hydroxylated chlorzoxazone with turnover numbers of 19.7 and 0.14 min(-1), respectively. Furthermore, cytochrome b5 stimulated chlorzoxazone 6-hydroxylation. From examination of the relative liver content of CYP2E1 and 3A, it can be asserted that CYP2E1 is the major enzyme involved in chlorzoxazone 6-hydroxylation and that the contribution of CYP3A is very minor. CYP2E1 activity was evaluated by the plasmatic metabolic ratio 6-OH-CHZ/CHZ (CHZ-MR) measured 2 h after ingestion of 500 mg CHZ. Smoker status did not influence the rate of CHZ hydroxylation. The CHZ-MR was 0.30 +/- 0.13 (mean +/- SD) n = 39 non-smokers versus 0.32 +/- 0.15, n = 75 smokers. This result suggests that CYP1A, inducible by cigarette smoking, is not significantly involved in chlorzoxazone hydroxylation. Women exhibited a slightly lower CHZ-MR than men (0.29 +/- 0.15, n = 44 versus 0.34 +/- 0.15 n = 49, respectively). Obesity increased CHZ-MR, especially in non-insulin-dependent diabetic individuals (0.45 +/- 0.21, n = 13 versus 0.30 +/- 0.15, n = 42 control individuals, P = 0.007). Furthermore, exposure of workers to volatile organics in a shoe factory decreased CHZ-MR (0.19 +/- 0.09, n = 10 Mexican workers versus 0.34 +/- 0.12, n = 16 Mexican control individuals, P = 0.001). Concomitant administration of grapefruit juice (known to be an inhibitor of CYP3A4) with chlorzoxazone did not significantly modify the CHZ metabolic ratio: 0.29 +/- 0.1 versus 0.31 +/- 0.1, for nine control individuals without and with grapefruit juice, respectively. In conclusion, all these results demonstrate that chlorzoxazone is a very selective probe for phenotyping CYP2E1 in humans.

Adult↗
PubMed1999

Immunochemical localization of platelet-derived growth factor in placenta and its possible role in pre-eclampsia.

BACKGROUND: Platelet-derived growth factor (PDGF) has an important role in cellular function, proliferation, and angiogenesis. It is also associated with tissue injury and repair, and its involvement in atherosclerosis has been studied extensively. Tissue injury is also found in pre-eclampsia (PRE). The morphological and physiological changes that are taking place in the PRE placenta may be associated with this growth factor. The objective of this study was to determine if PDGF-AA and its alpha receptor are present in the cells and vessels of normotensive (NORM) and PRE placentas at term. METHODS: Placental tissue was obtained from 6 preeclamptic and 8 normotensive women. Gestational age ranged from 38-42 weeks. Deliveries were either vaginal (vag, n = 10) or c-section (c-sec, n = 4). Tissue samples were analyzed for PDGF-AA by immunocytochemistry. RESULTS: PDGF-AA and the alpha receptor were present in both NORM and PRE placentas. Immunoreactive staining revealed PDGF-AA and its receptor in the intimal/endothelial layer of fetal vessels and the trophoblastic layer. Staining intensity was greater in preeclamptic tissue when obliterative endarteritis was present. CONCLUSIONS: In pre-eclampsia, PDGF-AA may play a role in the restructuring of the fetoplacental vasculature, in particular when there is inflammation of the vascular intimal layer, as found in obliterative endarteritis. Increased staining in the trophoblast layer in patients with obliterative endarteritis also may be indicative of more widespread damage throughout the placenta itself, and PDGF-AA may play a significant role in the repair of this damage.

Adolescent↗