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Biomedical subjects

B Brooks

Publications and source records attributed to B Brooks.

At least 19 recordsLinked to original sources
PubMed1997

Elevated serum progesterone levels during pituitary suppression may signify adrenal hyperandrogenism.

OBJECTIVE: To investigate whether elevated serum P levels after pituitary down-regulation signify adrenal enzyme defects or hyperandrogenism. DESIGN: Prospective study. SETTING: Assisted reproduction unit in a university medical center. PATIENT(S): Two hundred twenty-seven IVF patients treated by the long down-regulation protocol. INTERVENTION(S): Oral dexamethasone (DEX) administration if P level exceeded 0.8 ng/mL (conversion factor to SI unit, 3.180) after pituitary suppression. MAIN OUTCOME MEASURE(S): Serum concentrations of P, E2, LH, DHEAS, and 17 alpha-hydroxyprogesterone and ACTH stimulation tests. RESULT(S): In eight patients (3.5%), serum P levels exceeded 0.8 ng/mL and E2 and LH levels confirmed pituitary down-regulation. Mean DHEAS levels in the patients in this group were significantly higher than in the other patients. All eight patients demonstrated a significant decrease in serum P level after DEX administration. In five patients the ACTH stimulation test suggested an adrenal defect. Five pregnancies were achieved after the addition of DEX to the treatment protocol. CONCLUSION(S): High serum P levels after pituitary down-regulation appear to be of adrenal origin and may be the first indication of an adrenal enzyme defect. Further investigation such as an ACTH stimulation test is recommended, followed by treatment with DEX if indicated.

17-alpha-Hydroxyprogesterone↗
PubMed1996

Increased monocyte cytokine production in association with systemic complications in acute pancreatitis.

Tumour necrosis factor (TNF) alpha, interleukin (IL) 1 beta, IL-6 and IL-8 are thought to play a central role in the pathophysiology of sepsis but their role in acute pancreatitis is unknown. In the present study, monocytes were isolated from the peripheral blood of 26 patients with moderate or severe acute pancreatitis without biliary sepsis. Secretion of these cytokines in vitro was measured at intervals during the first week of illness. Sixteen patients developed systemic complications. Peak TNF-alpha secretion was significantly higher in patients who developed systemic complications (median (interquartile range (i.q.r.)) 18.5 (5.5-28.5) ng/ml) than in those with an uncomplicated course (3.7 (2.3-6.4) ng/ml, P < 0.01). Similarly, peak IL-6 and peak IL-8 secretion were significantly higher in the complicated group (IL-6: complicated median (i.q.r.) 48.9 (12.1-71.0) ng/ml, uncomplicated 16.3 (14.2-37.9) ng/ml, P < 0.05; IL-8: complicated 748 (643-901) ng/ml, uncomplicated 608 (496-749) ng/ml), P < 0.05). No significant difference in peak IL-1 beta secretion was observed between the two groups. Systemic complications of acute pancreatitis are associated with a significant increase in monocyte secretion of TNF-alpha, IL-6 and IL-8 suggesting that, as in sepsis, these cytokines play a central role in the pathophysiology of the disease.

Acute Disease↗
PubMed1996

Transfer of embryos from yeast-colonized dishes.

OBJECTIVE: To report yeast colonization in IVF dishes, where ET was carried out, and the IVF outcome was not compromised. DESIGN: Retrospective study of patients who underwent IVF cycle during the last 4 years. SETTING: In vitro fertilization program at the Shaare-Zedek hospital in Jerusalem. PATIENTS: Five couples who underwent standard IVF cycles and whose dishes were colonized with yeast. After thorough discussion ET was carried out. RESULTS: Although colonized with yeast, the quality of the embryos was not compromised. One to three of these embryos were transferred. All five women conceived. CONCLUSIONS: In vitro fertilization outcome is not necessarily compromised by yeast colonization. Nevertheless, the possible teratogenic effect of yeast on embryos has not been investigated and research is required to address this concern.

Adult↗
PubMed1996

Dissociating face processing skills: decision about lip-read speech, expression, and identity.

The separability of different subcomponents of face processing has been regularly affirmed, but not always so clearly demonstrated. In particular, the ability to extract speech from faces (lip-reading) has been shown to dissociate doubly from face identification in neurological but not in other populations. In this series of experiments with undergraduates, the classification of speech sound (lip-reading) from personally familiar and unfamiliar face photographs was explored using speeded manual responses. The independence of lip-reading from identity-based processing was confirmed. Furthermore, the established pattern of independence of expression-matching from, and dependence of identity-matching on, face familiarity was extended to personally familiar faces and "difficult"-emotion decisions. The implications of these findings are discussed.

Adolescent↗
PubMed1996

Immunological detection of lipopolysaccharide antigens of thermophilic campylobacters captured on polymyxin-coated polyester cloth.

Cholate-extracted lipopolysaccharide (LPS) antigens from thermophilic campylobacters were captured on polymyxin-coated polyester cloth. The captured antigens were detected by sequential reactions with rabbit anti-Campylobacter antibody, anti-rabbit IgG peroxidase conjugate and chromogenic peroxidase substrate. A polyclonal rabbit antibody elicited against a single Campylobacter-jejuni strain detected the reference strains of the twenty most frequently isolated thermophilic campylobacters in the Lior serotyping scheme. Moreover, LPS antigens of six C. Jejuni Penner serotypes fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and examined by immunoblotting were recognized by four antisera prepared against homologous and heterologous Penner serotypes. The results suggest the potential application of polymyxin-cloth enzyme immunoassay for rapid detection of thermophilic campylobacters where monoclonal antibodies can be raised to possible common LPS epitopes.

Animals↗
PubMed1995

Flow cytometric determination of intracellular calcium changes in human peripheral blood mononuclear cells during conjugation to tumour cell lines.

Using a flow cytometric assay, conjugate formation between human peripheral blood mononuclear cells (PBMC) and three different human tumour cell lines has been analysed. Changes in the intracellular calcium levels of PBMC were monitored using the calcium sensitive dye Fluo-3. Target cell populations were distinguished by forward scatter or following loading with the fluorescent dye, SNARF-1. Intracellular calcium was expressed as a ratio of fluorescence of conjugated to unconjugated PBMC and followed for ten minutes after initiation of conjugation. The results demonstrate an apparent increase in intracellular calcium in PBMC conjugated to the NK-sensitive cell line K562, and that the kinetics and magnitude of this response varied considerably between individuals. Tumour cells which were resistant to lysis (as determined in a 4 h chromium release assay) were also capable of eliciting a calcium response from PBMC. Although the induction of a rise in intracellular calcium was therefore not correlated with cytotoxicity, it was greater in IL-2-activated PBMC upon exposure to the same target cell lines as PBMC.

Aniline Compounds↗
PubMed1995

The long-term impact of urological management on the quality of life of children with spina bifida.

To evaluate the integration of children with spina bifida into adult society and identify important urological factors 20 female and 18 male spina bifida patients older than 18 years were evaluated with respect to urological management and complications. A detailed questionnaire concerning educational achievements, living arrangements, employment and interpersonal relationships was completed and compared to similar data obtained from the 1990 United States census. Educational achievement and living arrangements for most patients were comparable to age matched peers in the general population and were independent of gender or method of urinary management. The only statistically significant factor related to a positive outcome was female gender in the areas of employment (p < 0.014) and sexual relationships (p < 0.005). Female spina bifida patients adapted better to adult society than their male counterparts. Intestinal urinary conduits were detrimental to long-term renal function.

Adaptation, Psychological↗
PubMed1995

Body piercing: promoting informed decision making.

Although school nurses may be unfamiliar with adolescent body piercing, they are in a key position to assist students who are considering these procedures. Information about various types of body piercing, student experiences, and teaching strategies to talk with adolescents about this procedure are presented. Nurses can utilize the data to help students make informed decisions about body piercing.

Adolescent↗
PubMed1994

Mechanism of the reaction catalyzed by delta 5-3-ketosteroid isomerase of Comamonas (Pseudomonas) testosteroni: kinetic properties of a modified enzyme in which tyrosine 14 is replaced by 3-fluorotyrosine.

Tyrosine 14 of delta 5-3-ketosteroid isomerase plays an important role in the function of the enzyme, since its replacement by phenylalanine results in a decrease in kcat by a factor of 10(-4.7). This result and the fact that this residue resides in the enzyme's substrate binding site and is in close proximity to C-2 of the bound steroid suggests that it functions as an electrophile in the catalytic mechanism by protonation of or hydrogen bonding to the C-3 carbonyl oxygen of the substrate. In order to obtain more information about the role of tyrosine 14, we have prepared a modified form of the enzyme in which tyrosine 14 has been substantially replaced in vivo by exogenously supplied 3-fluorotyrosine, a tyrosine derivative in which the pKa' of the phenol hydroxyl should be decreased by about 1.5 log units. Site specificity of this modification has been ensured by mutation of the codons for the nonessential tyrosines 55 and 88 to phenylalanine. We find that replacement of tyrosine 14 by 3-fluorotyrosine in the Y55,88F modified form of the isomerase results in a 4-fold decrease in kcat. We interpret this result in terms of a mechanism in which the transition state for enolization is dienolate-like, characterized by relatively little proton transfer from tyrosine 14 in the transition state, and the intermediate in the overall reaction is dienol-like. An alternative mechanism in which the intermediate is stabilized by a short, strong hydrogen bond can also be consistent with the data.

Base Sequence↗
PubMed1994

Estimates of nuclear volume in plaque and tumor-stage mycosis fungoides. A new prognostic indicator.

It is well documented that mycosis fungoides (MF), a cutaneous T-cell lymphoma, has a variable clinical course. Unbiased stereological estimates of three-dimensional volume-weighted mean nuclear size (nucl vV) of mycosis cells were obtained in a retrospective study of 18 patients with a total of 34 biopsies of cutaneous plaque and tumor-stage MF. The value of nucl vV in the first sampled biopsy, as well as the average and highest values, were determined in biopsies from each patient. The patients were divided into two groups, either above or below the group median. There was a strong positive correlation between shorter survival and an average value of nucl vV > 104 microns 3 or a highest value of nucl vV > 126 microns 3 (2p = 0.002 and 0.003, respectively). A nucl vV > 91.6 microns 3 in the first biopsy was also suggestive of a shorter survival (2p = 0.07). There was no clear pattern of nucl vV evolution in the patients with multiple biopsies, but the impact of various therapeutic regimens cannot be assessed. Certain estimates of nucl vV appear to be good prognostic indicators in plaque and tumor-stage MF, but further study of a larger series of patients is needed to corroborate these results and assess the impact of differing therapeutic regimes.

Adult↗
PubMed1994

Australian National Diagnosis Related Groups and Abdominal surgery.

This study compares the declared splits for abdominal surgery within the Australian National Diagnosis Related Groups (AN-DRG) with age-based strata. Data were derived from two clinical trials involving 2114 adults. The patients tended to be elderly (25% > 71 years) and had significant co-morbidity, that is, 57% with an American Society of Anesthesia (ASA) classification > 1. Adverse events after surgery included pulmonary complications (16%), urinary tract infections (10%), wound infection (6%), and death (4.5%). Only 27% of the patients could be classified into a 'non-complicated' AN-DRG partition; these patients had a median age of 25 years and 88% had either appendicectomy or cholecystectomy. In contrast, analysis of six age-based strata revealed a stepwise increase in the incidence of adverse events after surgery (Friedman ANOVA, P < 0.001). It might therefore be wise to consider the inclusion of age-strata in the abdominal surgery component of the AN-DRG. Failure to do so may result in financial penalties for hospitals that care for patients at high risk of an adverse outcome after abdominal surgery.

Abdomen↗
PubMed1994

Obstructive sleep apnea in obese noninsulin-dependent diabetic patients: effect of continuous positive airway pressure treatment on insulin responsiveness.

Patients with noninsulin-dependent diabetes mellitus (NIDDM) are often obese and frequently complain of tiredness. These features are also characteristically seen in patients with obstructive sleep apnea (OSA). Therefore, it was the aim of this study to assess the prevalence of OSA among a group of obese NIDDM patients who have some clinical features of OSA. The effect of reversal of OSA by nasal continuous positive airway pressure (CPAP) treatment on insulin responsiveness was also investigated. From a population of 179 NIDDM patients with a body mass index (BMI) greater than 35 kg/m2, we performed ambulatory sleep monitoring on 31 (15 males and 16 females) who admitted to either heavy snoring or excessive sleepiness. Results were reviewed by a sleep physician blinded to the clinical status of the patients, and 22 (70%) were found to have moderate or severe OSA, with mean oxygen desaturation indexes of 10.3 +/- 5.3 and 30.7 +/- 13.2 episodes/h, respectively. A subgroup of 10 patients (seven males and three females) with a mean BMI of 42.7 +/- 4.3 kg/m2 was treated with nightly CPAP for 4 months. These subjects all had significant OSA, with frequent obstructive apneas (mean, 47 +/- 31.6 episodes/h) and oxygen desaturation (mean minimum O2 saturation, 74 +/- 9.5%), as determined by polysomnography. One patient was excluded from analysis because of infrequent use of CPAP. Insulin responsiveness in terms of glucose disposal measured by hyperinsulinemic euglycemic clamps improved from 11.4 +/- 6.2 to 15.1 +/- 4.6 mumol/kg.min (P < 0.05) during CPAP treatment. These results indicate that OSA occurs commonly in obese NIDDM patients with excessive sleepiness or heavy snoring. Treatment of their OSA may improve insulin responsiveness.

Adult↗
PubMed1994

Purification of class I medullipins from the venous effluent of isolated normal kidneys perfused under high pressure with saline.

Medullipin I (Med I) is a vasodepressor prohormone which is continuously elaborated into the renal venous effluent (RVE) of isolated rat kidneys perfused under high pressure. We have improved the yield of Med I by substituting saline for the albumin perfusate previously reported; and considerably improved refinement by directly fractionating the crude lipid extract of the RVE with high pressure liquid chromatography. The results show that Med I, as defined by previous physiologic and pharmacologic criteria, is not a single molecule. The 3 Class I medullipins described here are distinguished by subtle or overt differences in polarity and biologic activity.

Animals↗
PubMed1994

Secretion of medullipin I by the kidney involves the cytochrome P-450 enzyme system.

OBJECTIVE: To determine whether secretion of medullipin I by the kidney is dependent on the cytochrome P-450 enzyme system in Sprague-Dawley and spontaneously hypertensive rats (SHR). METHODS: Isolated kidneys from Sprague-Dawley rats were perfused with 5% human albumin gassed with 95% O2 and 5% CO2 at 185 mmHg. The resultant renal venous effluent was tested in the SHR for medullipin I-type vasodepressor activity. The kidneys were then treated with ketoconazole, and inhibitor of the cytochrome P-450 enzyme system. After rinsing with 50 ml saline, the last 10 ml of which was saved for a control test (see below), the kidneys were reperfused with 50 ml human albumin and the resultant renal venous effluent was tested for vasodepressor activity. One milliliter of the saline rinse was administered to the SHR and the preketoconazole renal venous effluent was administered after 15 min. The medullipin I-type vasodepression occurred. Thus, inhibition of vasodepression after ketoconazole treatment was not due to residual ketoconazole in the post-treatment renal venous effluent. RESULTS: Treatment of isolated kidneys with ketoconazole prevented secretion of medullipin I which had been induced by 5% human albumin. CONCLUSION: The cytochrome P-450 enzyme system is involved in two major metabolic steps of the medullipin system: synthesis of medullipin I by the kidney and conversion of medullipin I to medullipin II by the liver as shown previously.

Albumins↗
PubMed1993

Effects of hydroxyapatite implants on primary mineralization during rat tibial healing: biochemical and morphometric analyses.

The effect of 40- to 60-mesh hydroxyapatite (HA) granules (Calcitek, Inc., Carlsbad, CA) on the process of primary mineralization during bone healing was examined following insertion of the HA granules into rat tibial bone after marrow ablation. Response to HA was assessed by monitoring morphometric and biochemical changes in matrix vesicles, which are extracellular organelles associated with initial calcification. Following insertion of HA, matrix vesicle-enriched membranes (MVEMs) were isolated from the tissue adjacent to the implant and from the endosteum of the contralateral limb at 3, 6, 14, and 21 days and from a nonimplanted control group (t = 0). MVEM alkaline phosphatase- and phospholipase A2-specific activities were increased on days 6 (peak) and 14; phosphatidylserine content was also elevated on days 6 and 14 (peak). Comparable changes were seen in the contralateral limb but at lesser magnitudes. Morphological changes were observed as well. The number of matrix vesicles/micron2 matrix increased on days 6 (peak) and 14. The mean diameter of the matrix vesicles was elevated on days 6 (peak), 14, and 21. Mean distance from the calcifying front increased on day 6 but was decreased on days 14 and 21. These results indicated that HA behaves like bone-bonding implants in that there is a stimulation of matrix vesicle enzymes, increased phosphatidylserine content, and increase numbers of matrix vesicles. However, the increases occur only after 6 days postimplantation, indicating a delay in response when compared to normal healing. This delay is confirmed by the morphometric measurements. HA causes a reduction in the response associated with marrow ablation. In addition, the effects of HA are comparable locally and systemically but with different intensity. These observations suggest that osteogenic cells are able to compensate for the inhibitory effects of HA and primary calcification involves normal matrix vesicle production and maturation, if somewhat delayed and reduced in magnitude. The ability to support primary mineral formation may contribute to the successful bonding of HA with surrounding osseous tissue.

Alkaline Phosphatase↗