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Biomedical subjects

M Bates

Publications and source records attributed to M Bates.

At least 19 recordsLinked to original sources
PubMed2005

Does the use of 50% oxygen at birth in preterm infants reduce lung injury?

BACKGROUND: Bronchopulmonary dysplasia is an inflammatory fibrotic condition produced as a consequence of injurious influences in the neonatal lung. Exposing the premature lung to high concentrations of oxygen is thought to play an important part in lung injury pathogenesis. OBJECTIVE: To see if the amount of oxygen used during resuscitation at birth triggers events that lead to the subsequent lung injury and if a reduction in oxygen used leads to a reduction in lung injury. METHOD: The outcomes of newborn babies less than 31 weeks gestation who were resuscitated using either 50% or 100% oxygen were examined. Eight of the babies receiving 50% oxygen required an increase in their oxygen concentration. Evidence of pulmonary inflammation was determined by quantifying interleukin 6, 1beta, and 10 and tumour necrosis factor alpha in bronchoalveolar lavage fluid by enzyme linked immunosorbent assay. RESULTS: There were no significant differences in any of the cytokines studied in either of the groups. Death occurred in 5/26 (19%) babies who received 100% oxygen and 4/26 (15%) babies who received 50% oxygen. Survival without bronchopulmonary dysplasia at 36 weeks postmenstrual age occurred in 14/26 (54%) and 13/26 (50%). CONCLUSION: Reducing the oxygen to 50% at resuscitation did not influence either short or long term outcomes, but a small benefit could not be excluded. There was no increase in adverse clinical outcomes in babies who received 100% oxygen.

Asphyxia Neonatorum↗
PubMed2005

Does sustained lung inflation at resuscitation reduce lung injury in the preterm infant?

BACKGROUND: Bronchopulmonary dysplasia (BPD) is a common outcome of preterm birth. Experimental animal work has shown that initial ventilation strategies injure the immature lung and may lead to BPD. Studies with asphyxiated babies have shown that, if tidal ventilation at birth is preceded by sustained lung inflation, larger inflation volumes can be achieved, which is thought to lead to clearance of lung fluid and formation of the functional residual capacity (FRC). OBJECTIVE: To see if sustained lung inflation at initial resuscitation of preterm babies would facilitate the removal of lung fluid, establish the FRC, and allow an even distribution of alveolar opening, permitting less aggressive ventilation, leading to a reduction in pulmonary inflammation and subsequent BPD. METHOD: The outcomes of 52 babies of less than 31 weeks gestation, resuscitated at birth using either a sustained lung inflation of five seconds or a conventional lung inflation of two seconds for the first assisted breath of resuscitation, were examined. Evidence of pulmonary inflammation was determined by quantification of interleukins 6, 10, and 1beta and tumour necrosis factor alpha in bronchoalveolar lavage fluid by enzyme linked immunosorbent assay. RESULTS: There were no significant differences in any of the cytokines. Death occurred in 3/26 babies in the conventional group and 6/26 babies in the sustained lung inflation group. Survival without BPD occurred in 13/26 and 14/26 respectively. CONCLUSION: The use of sustained lung inflation at resuscitation did not reduce lung injury, as measured by inflammatory markers.

Asphyxia Neonatorum↗
PubMed2004

Is there a relationship between treatment for infertility and gestational trophoblastic disease?

BACKGROUND: The aim of the study was to record the incidence of treatment for infertility prior to development of gestational trophoblastic disease (GTD). METHODS AND RESULTS: A retrospective analysis was undertaken of 231 consecutive women receiving chemotherapy for persistent GTD at Weston Park Hospital, Sheffield, from 1991 to 2001. Three patients in this group had received treatment for infertility prior to their molar pregnancy. In a control group of 226 patients not requiring treatment for persistent GTD, four had had treatment for infertility just before their molar pregnancy, and in a further control group of 208 'normal' pregnancies, eight patients had had treatment for infertility prior to conception. CONCLUSION: We conclude that we can demonstrate no relationship between infertility treatment and subsequent development of GTD.

Adult↗
PubMed2003

Performance of the CELSS Antarctic Analog Project (CAAP) crop production system.

Regenerative life support systems potentially offer a level of self-sufficiency and a decrease in logistics and associated costs in support of space exploration and habitation missions. Current state-of-the-art in plant-based, regenerative life support requires resources in excess of allocation proposed for candidate mission scenarios. Feasibility thresholds have been identified for candidate exploration missions. The goal of this paper is to review recent advances in performance achieved in the CELSS Antarctic Analog Project (CAAP) in light of the likely resource constraints. A prototype CAAP crop production chamber has been constructed and operated at the Ames Research Center. The chamber includes a number of unique hardware and software components focused on attempts to increase production efficiency, increase energy efficiency, and control the flow of energy and mass through the system. Both single crop, batch production and continuous cultivation of mixed crops production studies have been completed. The crop productivity as well as engineering performance of the chamber are described. For each scenario, energy required and partitioned for lighting, cooling, pumping, fans, etc. is quantified. Crop production and the resulting lighting efficiency and energy conversion efficiencies are presented. In the mixed-crop scenario, with 27 different crops under cultivation, 17 m2 of crop area provided a mean of 515 g edible biomass per day (85% of the approximate 620 g required for one person). Enhanced engineering and crop production performance achieved with the CAAP chamber, compared with current state-of-the-art, places plant-based life support systems at the threshold of feasibility.

Agriculture↗
PubMed2003

Comparison of colonoscopies performed under sedation with propofol or with midazolam or without sedation.

BACKGROUND: Previous studies have shown that some patients are not able to tolerate colonoscopy without sedation because of low pain threshold, anxiety, colonic sensitivity and anatomical variations. Benzodiazepines are most commonly used, often in combination with pethidine. Our study compares sedation with propofol to midazolam and colonoscopy without sedation. METHODS: In this study 147 patients were examined. The patients were divided into three groups: The first group included patients in whom propofol was used for sedation, the second group included patients sedated with midazolam, and the third group was comprised of patients who received no sedation. Oxygen saturation and heart rate were recorded continuously by pulse oxymetry. Arterial blood pressure (BP) was monitored at 3-min intervals. RESULTS: A decrease in blood pressure and heart rate was documented in the first two groups (P < 0.001), whereas in group 3 we found an increase in both BP and heart rate (P < 0.001). Oxygen saturation dropped below 90 % in 11/102 patients sedated with propofol and in 9/23 sedated with midazolam. Two of 22 patients in whom no sedation was used were found to have oxygen saturation below 90 %. The recovery time was shorter (7 min) in group 1 (propofol) than in group 2 (midazolam), in which it was found to be 20 min. CONCLUSIONS: Our results showed that propofol provided good sedation with excellent pain control, a short recovery time and no significant haemodynamic side effects.

Adolescent↗
PubMed2001

Evaluating panic-specific factors in the relationship between suicide and panic disorder.

Work during the past decade has suggested an association between panic disorder and suicide (i.e., suicidal ideation and suicide attempts) that cannot simply be accounted for by co-occurring depression symptoms. To clarify the linkage between panic disorder and suicide, the association between panic-specific clinical and cognitive variables and suicide indicators were evaluated in patients with panic disorder (N=146). Analyses predicting the presence of suicidal ideation (positive, negative) after covarying the effects of a current mood disorder diagnosis and depression symptoms indicated a number of significant predictors including: (1) overall anxiety symptoms; (2) level of anticipatory anxiety; (3) avoidance of bodily sensations; (4) attentional vigilance toward bodily perturbations; and (5) phrenophobia (i.e., fear of cognitive incapacitation). Anxiety-specific variables did not account for unique variance in predicting prior history of suicide attempts.

Adult↗
PubMed2001

Cytokine promoter gene polymorphisms and idiopathic recurrent pregnancy loss.

Approximately one in 300 women experience recurrent pregnancy loss (RPL), the aetiology of which is unknown in at least 40% of cases. Previously, some studies have shown increased production of pro-inflammatory cytokines (tumour necrosis factor-alpha and interferon-gamma) and reduced production of anti-inflammatory cytokines (interleukin-10) by circulating blood lymphocytes isolated from these patients when compared with controls. The reasons for this are unclear. The production of these cytokines are partly under genetic control. This study investigated whether polymorphisms in these three cytokine genes known to be associated with either high or low production, are associated with idiopathic RPL. No association was found. It may be that genetic factors are not a major determinant of cytokine production during pregnancy, or alternatively it may be that the observed differences in cytokine production by peripheral lymphocytes do not accurately indicate what is occurring at the local maternofoetal interface during successful and abortive pregnancies.

Abortion, Habitual↗
PubMed2001

Efficacy of a proximal occlusion catheter with reversal of flow in the prevention of embolic events during carotid artery stenting: an experimental analysis.

OBJECTIVE: The role of percutaneous angioplasty and stenting of carotid bifurcation lesions has been limited by its potential for producing embolic debris. We evaluated the efficacy of a proximal occlusion catheter (POC) in the prevention of embolic events during carotid artery stenting. In addition, pressure measurements relevant to the clinical application of this device were obtained from 10 patients undergoing carotid endarterectomy. METHODS: The POC is a guiding catheter with an occlusion balloon attached on the outside of the catheter at its distal end. Occlusion of the common carotid artery (CCA) was achieved by inflating the balloon while access to carotid bifurcation lesions was obtained through the inner lumen. The POC was inserted in the CCA of 10 dogs via the femoral artery. The side port of the POC was connected to a sheath placed in the femoral vein, thereby creating an external arteriovenous shunt. Ten artificial radiopaque particles simulating embolic particles and contrast agent were introduced in the CCA and monitored fluoroscopically. As a control, the same procedure was performed with a standard guiding catheter without an occlusion balloon. In 10 patients undergoing carotid endarterectomy, the internal carotid artery (ICA) and external carotid artery stump pressures and the pressure in the internal jugular vein were measured. RESULTS: Without the external arteriovenous shunt, in all animals there was prograde flow in the distal CCA despite CCA occlusion. This flow was derived from the thyroid artery. However, once the arteriovenous shunt was activated, reversal of flow in the distal CCA was achieved in each animal, and all the artificial particles were recovered from the side port of the POC. In the control group, each particle embolized to the brain (100%, P <.01). In the patients, the mean stump pressures in the ICA and external carotid artery and the jugular vein pressure were 51.8 +/- 14.2, 62.2 +/- 15.1, and 6.5 +/- 3.5 mm Hg, respectively. In each case, the jugular vein pressure was the lowest among the three. CONCLUSIONS: Obtaining proximal CCA control by inflating the POC does not sufficiently prevent embolization. However, reversal of flow in the ICA can always be created with the external shunt, which effectively prevents embolization. Thus, POC may markedly lower procedural stroke rates during carotid artery stenting. The ability of POC to prevent embolization before crossing the lesion with a guidewire may be an important advantage over other distal protection devices.

Angioplasty, Balloon↗
PubMed2001

Concentration of interleukin-12 in the peritoneal fluid is not influenced by the presence of endometriosis, its stage or the phase of the menstrual cycle.

BACKGROUND: IL-12 is a key immunomodulatory cytokine. Its presence or concentration in peritoneal fluid is not related to the presence of endometriosis or the stage of the disease. A study was carried out to gain insight into the role of IL-12 in the development and maintenance of endometriosis in relation to menstrual cycle. METHODS: A prospective study recruiting 64 consecutive women undergoing laparoscopic surgery for benign gynecological indications. Peritoneal fluid was obtained during laparoscopy. Concentration of IL-12 was measured and correlated to the presence of endometriosis, its stage and the phase of the menstrual cycle. RESULT(S): Peritoneal fluid concentrations of IL-12 showed no correlation with the presence of endometriosis, the AFS stage of the disease or the phase of the menstrual cycle. CONCLUSION(S): IL-12 is a normal constituent of peritoneal fluid in around one third of the population tested and is not involved in the pathogenesis of endometriosis at any stage of the disease or the phase of the menstrual cycle.

Ascitic Fluid↗
PubMed2000

Follicular fluid concentrations of interleukin-12 and interleukin-8 in IVF cycles.

OBJECTIVE: To investigate the role of interleukin-12 (IL-12) and IL-8 in the periovulatory follicular fluid during in vitro fertilization cycles. DESIGN: A prospective study. SETTING: Reproductive Medicine Unit, Liverpool Women's Hospital, United Kingdom. PATIENT(S): Women undergoing in vitro fertilization treatment. INTERVENTION(S): IL-8 and IL-12 concentrations in follicular fluid samples that had been collected during transvaginal oocyte retrieval were measured using an enzyme-linked immunosorbent assay (ELISA). Cytokine concentrations were correlated to fertilization rates and treatment outcome. MAIN OUTCOME MEASURE(S): Fertilization rates and ultrasonographic evidence of intrauterine pregnancy by 4 weeks after embryo transfer. RESULT(S): Failed fertilization in women with detectable IL-12 was significantly higher (45.5%) than in the IL-12 negative group (6.1%), P=.01. None of the women with detectable IL-12 achieved a pregnancy at the end of the treatment (P=.01). IL-8 was present in the follicular fluid of all women, and no difference in its concentrations was found between the pregnant and nonpregnant groups. No correlation was found between the follicular fluid concentrations of IL-8 and fertilization rates. CONCLUSION(S): The presence of IL-12 in the follicular fluid appears to be associated with a negative outcome in IVF treatment. Interleukin-8 appears to be an essential part of folliculogenesis, although its concentration is not associated with fertilization or implantation rates.

Adult↗
PubMed2000

Peritoneal fluid concentrations of interleukin-11 in women with endometriosis.

OBJECTIVE: To determine the peritoneal fluid concentrations of interleukin-11 (IL-11) in women with endometriosis as compared with the control group. DESIGN: A prospective, controlled study. SETTING: The obstetrics and gynecology department of a teaching hospital and a university immunology department. PATIENT(S): Sixty consecutive women undergoing laparoscopic surgery for benign gynecological indications. INTERVENTION(S): Peritoneal fluid was obtained during laparoscopy, and the concentration of IL-11 was measured. MAIN OUTCOME MEASURE(S): Concentration of IL-11 in correlation with the presence of endometriosis, its stage, and the phase of the menstrual cycle. RESULT(S): IL-11 was detectable in the peritoneal fluid of 64% of women tested. Concentrations of IL-11 showed no correlation with the presence of endometriosis, the American Fertility Society stage of the disease, or the phase of the menstrual cycle. CONCLUSION(S): We found no evidence to suggest that IL-11 is involved in the pathogenesis of pelvic endometriosis.

Adult↗
PubMed2000

Emergency repair of type A aortic dissection in type IV Ehlers-Danlos syndrome.

Ehlers-Danlos syndrome type IV is a distinctive syndrome in which thin and fragile skin, premature ageing, bruising and scarring are combined with lethal or life-threatening arterial weakness. Aortic rupture either at the aortic root and arch, or sometimes lower down the artery, are particularly characteristic. Even quite minor injury can produce dangerous vascular tearing and damage. Technical difficulties encountered in arterial repair or venous ligature are particularly worrying. The authors report the treatment of a ruptured type A aortic dissection associated with Ehlers-Danlos syndrome where the extreme fragility of the tissues and tendency to bleed posed a difficult task for the surgeon.

Adult↗
PubMed1999

Evaluation of a smoking cessation programme that uses behaviour modification.

AIM: To obtain an up-to-date measure of the end-of-course success rate of the Isis Stop Smoking Programme and to determine which demographic, socioeconomic and behavioural factors were predictors of success in the programme. METHOD: Data from a questionnaire completed at the outset of course participation were available for 1016 Isis participants. The data were statistically analysed. RESULTS: "Success" was defined as having consumed no cigarettes during the final 24 hours of participation on the Isis Programme. The overall success rate at completion of the programme was 69% of participants. For both males and females, the number of cigarettes consumed on beginning the programme was the strongest predictor of success. Other predictors were commitment to quitting, nicotine yield of the usual cigarette, number of years of smoking and age. Young females had a particularly good success rate. Participants were categorised according to the New Zealand Socioeconomic Index of Occupational Status. Professional and technical workers were the most successful quitters and the unemployed, self-employed and students had particularly low success rates. CONCLUSION: Assuming proportionality of recent end-of-course success rates with comparable figures from the late 1970s, the proportion of Isis participants who continue to be non-smokers one year from completing the course would be approximately 33%. Further investigation to confirm this is warranted.

Adolescent↗
PubMed1999

Effects of aerobic exercise on serum leptin levels in obese women.

It has been demonstrated that leptin concentrations in obese patients may be altered by weight loss. We examined the effects of a 9-week aerobic exercise program on serum leptin concentrations in overweight women (20-50% above ideal body mass) under conditions of weight stability. Sixteen overweight women, mean (SE) age 42.75 (1.64) years, comprised the exercise group which adhered to a supervised aerobic exercise program. A graded exercise treadmill test was conducted before and after the exercise program to determine maximal oxygen uptake (VO2max) using open-circuit spirometry. The women demonstrated improved aerobic fitness (VO2max increased 12.29%), however, body fat and the body mass index did not change significantly [42.27 (1.35)-41.87 (1.33)%]. Fourteen women, age 40.57 (2.80) years, did not exercise over the same time period and served as a control group. Serum leptin levels were not significantly altered for either the exercise [28.00 (2.13)-31.04 (2.71) ng x ml(-1)] or the control group [33.24 (3.78)-34.69 (3.14) ng x mg(-1)]. The data indicate that 9 weeks of aerobic exercise improves aerobic fitness, but does not affect leptin concentrations in overweight women.

Adult↗
PubMed1999

Optimal time for distraction osteogenesis in limbs with nerve repairs: experimental study in the rat.

The optimal period of time between peripheral-nerve repair and initiation of limb lengthening procedures has never been precisely determined. In the clinical setting, the surgeon must decide how long the repaired nerves should be allowed to heal before subjecting them to the forces created by the limb-lengthening process. The authors designed a study to quantify and qualify the effects of different recovery periods between initial nerve repair and subsequent limb-lengthening via distraction osteogenesis. Forty-two Sprague-Dawley male rats were randomized in two different categories of nerve repair: end-to-end and nerve grafts. At 4, 8 and 12 weeks after nerve reconstruction, the femur was submitted to limb-lengthening at a rate of 1 mm/day (0.25 mm every 6 hr). Sciatic Function Index (SFI) evaluation indicated that the impact of distraction was detrimental in the grafted nerves, although they maintained their electrical and morphologic properties at comparable levels to the non-distracted nerves. Nerves with direct coaptation presented an overall superior regeneration pattern. The findings in end-to-end repairs distracted at 8 weeks and those of grafted nerves at 12 weeks were comparable to those in distracted normal nerves. The morphology of the distracted nerves appeared to be more organized than that observed in the non-distracted nerves.

Animals↗
PubMed1999

Pre-implantation endometrial leukocytes in women with recurrent miscarriage.

Immunohistochemistry was used to investigate the leukocyte populations in the endometrium of women suffering recurrent miscarriage. Mid-luteal phase endometrial biopsies were taken from 22 patients with idiopathic recurrent miscarriage and from nine women with normal obstetric histories. The samples were dated histologically and stained with a panel of monoclonal antibodies to identify leukocytes. The outcome of any pregnancy in subsequent cycles following the biopsy was determined. Similar numbers of cluster designation (CD)3(+) and CD8(+) cells were seen in both groups. However, CD4(+), CD14(+), CD16(+), CD56(+) and MHC class II(+) cells were significantly higher in the recurrent miscarriage group than in the controls. Two patients had B cells (CD22(+)) in their endometrium. No CD57(+) cells were seen in the controls; however, eight of the patients had a few CD57(+) cells present. Only two patients, both from the recurrent miscarriage group, had CD69(+) leukocytes in their endometrium. Patients who had miscarriages following endometrial biopsy had significantly more CD4(+), CD8(+), CD14(+), CD16(+), and CD56(+) leukocytes in their endometrium than either those who had live births or women with proven fertility. A different population of leukocytes was found in the pre-implantation endometrium from recurrent miscarriage patients as compared to those from fertile controls. These differences were accentuated in women who had a miscarriage subsequent to the biopsy compared with those who subsequently had a live birth.

Abortion, Habitual↗
PubMed1998

The incidence of hepatocellular carcinoma in New Zealand.

AIM: To measure the incidence rate of hepatocellular carcinoma (HCC) in New Zealand, by ethnicity, sex, region and age. METHODS: Cancer Registry data for 1983-94 were used to calculate rates of primary liver cancer (ICD code 155.0) and HCC (both ICD code 155.0 and ICD-O morphology code 8170) directly standardised to Segi's world population and standardised for region. RESULTS: Rates of HCC per 100,000 person years 6.6 and 1.3 for Maori males and females, 14.7 and 4.6 for Pacific people, and 0.8 and 0.3 for Other (inclusive of Chinese). The rates for Chinese for 1989-94 were 19.9 and 5.8. These rates are likely to be underestimates due to imperfect sensitivity of ICD-O code 8170 registrations for HCC. The rates of HCC for Maori and Pacific people (sexes combined) were 7.3 and 18.0 times that for other for 1983-94; the HCC rate for Chinese was 25.8 times greater than Europeans for 1989-94. Rates of HCC tended to be higher in the north of New Zealand, compared to the south, for Maori and Other/Europeans, but there was no apparent regional gradient for Pacific people and Chinese. CONCLUSIONS: Non-Europeans have higher rates of HCC than Europeans due to variations in hepatitis B carriage. Males have higher rates than females, and Maori and Europeans living in the north of New Zealand have higher rates of HCC than those living in the south. It is estimated that any hepatitis B screening and follow-up programme will detect one incident case of HCC per year per 2000 hepatitis B carriers in the target population, or one incident case per 1000 carriers actually participating in regular follow-up.

Carcinoma, Hepatocellular↗