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Biomedical subjects

P Kent

Publications and source records attributed to P Kent.

At least 37 records · Page 2Linked to original sources
PubMed1997

Pharmaco-ontogeny of bombesin's suppression of food intake and its attenuation by histamine H3 receptor agonists.

Bombesin (BN) administration has been shown to suppress food intake across diverse species. Preliminary results have shown that BN elicits a satiety-like state from postnatal day (PD) 1, through unknown mechanism(s). We have recently shown that in adult rats, alpha-methyl histamine (alpha-MH), a selective H3 receptor agonist that inhibits the release and synthesis of histamine, blocks the feeding suppressant effects of BN. The objective of this study was to determine if such a mechanism was operation at birth or whether it developed over time. Thus effects of histamine H3 receptor agonists as well as BN-histamine interactions in the regulation of food intake were assessed during early development. On PD 1, 5, 10 and 15, groups of food deprived Sprague-Dawley rat pups (n = 8-12) were injected with BN alone (0 (saline), 0.006, 0.06 or 0.6 mg/kg, s.c.), H3 receptor agonists alone (alpha-MH or Imetit (3 or 5 mg/kg s.c.)) or the combination of BN and H3 receptor agonists, and their ingestive behavior was monitored. Results confirmed that pups were sensitive to feeding suppressant effects of BN starting from PD 1. Imetit or alpha-MH either failed to affect food intake or at certain time points enhanced food intake. Pretreatment with the H3 receptor agonists significantly attenuated the feeding suppressant effects of BN, suggesting that early in ontogeny, BN may suppress food ingestion possibly by facilitating histamine release at some relevant site(s).

Analysis of Variance↗
PubMed1997

Influence of psychogenic and neurogenic stressors on endocrine and immune activity: differential effects in fast and slow seizing rat strains.

Variations of plasma ACTH and corticosterone, as well as splenic macrophage activity and mitogen-induced cell proliferation, were determined in rats following 15 min of either the neurogenic stressor of restraint or by a purely psychogenic stressor consisting of exposure to a ferret. The effects of these stressors were assessed in two strains of rats that were selectively bred for either Fast or Slow kindling epileptogenesis triggered in response to amygdala stimulation. The stressors differentially influenced behavioral responses, endocrine activity, and immune functioning, and these effects varied with the strain of rat. In response to restraint the Fast rats exhibited protracted struggling, while the Slow rats tended to be immobile. In contrast, upon ferret exposure the Fast rats showed greater immobility than the Slow rats. The stressors also induced marked elevations of plasma ACTH and corticosterone. Whereas the ACTH and corticosterone increases were more pronounced in response to the ferret in the Slow rats, restraint resulted in a markedly greater rise of plasma ACTH in the Fast strain. Proliferation of splenic lymphocytes in response to Con A and LPS were elevated in Fast seizing rats, while macrophage activity, as determined by oxygen burst following addition of PMA and luminol to splenic mononuclear cells, was greater in the Slow seizing strain. While neither stressor influenced cell proliferation in either the Fast or Slow rats, macrophage activity was greatly suppressed by ferret exposure only in the Slow rats. Taken together, it appears that while stressors influence behavior and immune and endocrine functioning, these effects may vary as a function of the interaction of the strain of rat and the specific type of stressor employed.

Adrenocorticotropic Hormone↗
PubMed1997

Predicting episodic memory performance of very old men and women: contributions from age, depression, activity, cognitive ability, and speed.

Regression models were developed to explain age-related and total variance in memory and to determine the independent contribution from general processing speed, having taken into account cognitive and noncognitive individual differences. Episodic memory was assessed for 3 tasks in a population-based sample of 951 adults comprising 515 men and 436 women (aged 70-96, M = 77.6, SD = 5.5). Correlations between age and memory accounted for 6%-9% of the variance. Hierarchical multiple regressions showed a reduction in this age-related variance by up to 94%, after entering gender, depression, health, cognitive status, activities, and speed. General processing speed was the major mediator of age-related variance in memory. Although both the age-related variance and the speed-related variance in memory were significantly reduced by prior entry of other individual differences variables for all 3 tasks, speed remained a significant mediator of remembering, and negligible differences in the residual age-related variance were observed by inclusion of other background variables.

Activities of Daily Living↗
PubMed1996

Pediatric large volume peripheral blood progenitor cell collections from patients under 25 kg: a primer.

Collection of peripheral blood progenitor cells from small pediatric patients provides many social and technical challenges not faced when collecting from adult patients. This paper provides a single institutions experience with 85 collections from 14 patients less than 25 kg of weight over a 2 year period. Specific challenges include obtaining venous access, anticoagulation, volume shifts, and obtaining patient cooperation. A systematic analysis of options for access, alternative modes of anticoagulation, and the effect of large ratios of extra-corporeal volume to patient's blood volume are discussed. Access uniformly required central venous catheters (CVC) ranging from 7-10 Fr. Anticoagulation included systemic heparinization titrating dose by activated clotting time in all cases and combined with citrate at a ratio of 1:25-1:30 in most cases. Collections were performed on a COBE Spectra, after priming with leukoreduced irradiated red cells and omitting both the initial 120cc diversion and rinse back of red cells at the end. Social challenges include issues of assent and ability to distract patients for the duration of a prolonged collection. Progenitor yields from collections from 14 patients were quantitated by CD34+ assay in all cases and CFU-GM in ten of 14 patients. A median of 4.5 x 10(6)/kg CD34+ cells were obtained for each collection. Complications, including those related to catheter access, are enumerated. In summary, large volume peripheral blood progenitor collection can be safely and efficaciously performed in small pediatric patients.

Body Weight↗
PubMed1996

Large-volume leukapheresis in pediatric patients: processing more blood diminishes the apparent magnitude of intra-apheresis recruitment.

BACKGROUND: Recruitment of progenitors during a large-volume collection, as defined by increasing relative and absolute numbers of progenitors (colony-forming units-granulocyte-macrophage [CFU-GM] of CD34+ cells), has been reported previously. STUDY DESIGN AND METHODS: To ascertain whether intra-apheresis recruitment occurs in pediatric patients who have undergone mobilization with chemotherapy and granulocyte-colony-stimulating factor (G-CSF), each hour's portion of a 4-hour leukapheresis was collected into separate bags, and assessed by complete blood count, CFU-GM, and CD34+ cell assays. Seven pediatric patients (median age, 7; range, 2-19) were studied in connection with 2 to 4 collections each, for a total of 21 collections (with hourly samples). The collections lasted for 4 hours, at an inlet rate of 1 to 3 mL per kg per minute, for daily processing totals of 5 to 12 blood volumes. (One blood volume [mL] is estimated by the patient's weight in kg x 70 mL/kg.) Smaller (younger) patients had inlet rates exceeding 2 mL per kg per minute, and larger (older) patients had rates of 1 to 1.5 mL per kg per minute. CFU-GM and CD34+ cell counts obtained each hour of the collection and divided by the first hour's value were compared by nonparametric repeated-measures ANOVA. RESULTS: Second-, third- and fourth-hour CD34+ progenitor cell counts were arithmetically higher than first-hour counts, but the trend did not reach significance (p = 0.1561). Second-hour counts were higher than first-hour counts in the overall analysis (mean +/- standard error [SE], 1.00 and 1.39 +/- 0.1, respectively; p = 0.0525) and in children older than 5 years (1.00 vs. 1.70 +/- 0.30, respectively; p = 0.0259), but not in children younger than 5 years (p = 0.8125). CFU-GM counts did not differ among the 4 hours of collection (p = 0.1717) or between the first and second hour (p = 0.9587). CONCLUSION: In larger (older) patients, from whom fewer blood volumes were collected, there is a trend toward intra-apheresis recruitment, although less than reported previously. In the smaller (younger) patients, from whom more blood volumes were collected, no trend was observed. Lack of (or submaximal) prior mobilization in previously reported studies may have facilitated intracollection recruitment. Alternatively, the larger number of blood volumes collected from the smaller (younger) patients may have masked intra-apheresis recruitment. The study documents the feasibility of large-volume, 4-hour leukapheresis in pediatric patients.

Adolescent↗
PubMed1996

Smoking behaviours and beliefs of older Australians.

Reviews of the effects of smoking on health have concluded that older smokers can experience considerable health benefits from giving up smoking. In a representative population survey of people aged 15 years and over in South Australia, the percentage of people aged 60 years and over who were smokers was 13.5 per cent (95 per cent confidence interval 10.9 to 16.2 per cent). Compared with smokers aged under 60 years (n = 727), older smokers (n = 88) were significantly more likely: to be less convinced of the effects of smoking on health; to perceive that they were not personally at risk from their smoking in the future; to believe that smoking had not affected their own health so far; and to believe there was a daily level of cigarette consumption that was safe. Strategies to encourage older people to consider more objectively how smoking impairs daily living, including personal disclosure of smoking-related damage through lung-function testing, deserve further research.

Adult↗
PubMed1996

Casemix and affective disorders: a comparison of private and public psychiatric systems.

OBJECTIVE: To determine whether there is a difference in length of stay for patients with affective disorders between private and public psychiatric hospitals. METHOD: The casemix Australian national diagnosis-related group (AN-DRG) diagnoses of all inpatient separations from private and public psychiatric hospitals in South Australia for 1 year were abstracted from records. The average length of stay for patients with affective disorders was calculated. RESULTS: There was no significant difference in the average length of stay for patients with affective disorders treated in private and public psychiatric hospitals. CONCLUSIONS: These results should allay fears that the treatment of patients with affective disorders in any particular treatment setting will be compromised by the introduction of casemix.

Affective Disorders, Psychotic↗
PubMed1995

Intensive blood and plasma exchange for treatment of coagulopathy in meningococcemia.

Eight pediatric patients with fulminant meningococcemia, purpura, and disseminated intravascular cogulation who by multiple prognostic scoring systems were anticipated to have a poor outcome underwent intensive plasma exchange (IPE) or whole blood exchange (WBE) in addition to standard medical therapy. IPE/WBE was initiated shortly after admission with a mixture of both fresh frozen plasma and cryoprecipitate as the replacement solution. All IPE procedures were performed using a continuous flow system and a red cell prime. The mean fibrinogen level increased from 62 to 192 mg/dl, the prothrombin time (PT) decreased from a mean of 32.4 seconds to 15.1 seconds, and the mean activated partial thromboplastin time (APTT) decreased from 89.5 seconds to 40.1 seconds following completion of the initial IPE/WBE. There was a corresponding improvement in all coagulation factor levels but only slight improvement in antithrombin III (ATIII) and protein C levels. Seven of eight patients survived (87.5%) their initial presentation with the sole early death attributed to meningitis with cerebral edema. Mean fluid balance after the procedure was +10.8 +/- 5.87 cc/kg. There were no significant bleeding or cardiovascular complications during the procedure. There was no clinical or radiographic evidence of fluid overload after the procedure. This experience demonstrates that IPE/WBE may be conducted safely in critically ill, unstable pediatric patients and is effective in rapidly improving coagulopathy without fluid overload.

Adolescent↗
PubMed1995

Low-rate smokers.

BACKGROUND: Some smokers maintain a low daily smoking rate and do not appear to be addicted to nicotine (tobacco "chippers"). In a context of increasing social and environmental constraints on cigarette smoking, it is of interest to determine the population prevalence and the characteristics of low-rate smoking behavior. METHODS: A representative population survey was used to determine the prevalence and the correlates of low-rate smoking (five or less cigarettes a day). A range of sociodemographic, contextual, cognitive, and smoking-behavior variables was examined. RESULTS: Of 697 smokers age 20 years and over who had smoked for more than 2 years, 8.2% smoked five or less cigarettes a day; their average age was 39 years, and half were under 35 years of age; 88% had been smoking for 6 or more years; 86% were in the contemplation or preparation stages of readiness to quit. The significant independent predictors of being a low-rate smoker, compared to smoking at a higher daily rate, were perceiving quitting as not very difficult, smoking the first cigarette of the day more than 30 min after walking, buying packets of 30 or less cigarettes, and having not been advised by a doctor to quit. CONCLUSIONS: There were few differences between low-rate and other smokers on the range of variables that we were able to assess in a population survey. Since there is no safe level of cigarette smoking, medical advice to quit and public-education campaigns could target low-rate smokers specifically. Such initiatives could make significant contributions to reducing overall smoking prevalence.

Adult↗
PubMed1995

Skin closure and the incidence of groin wound infection: a prospective study.

Groin wound infection is a dreaded complication of vascular surgery and may jeopardize an underlying graft. A variety of skin closures have been used and the object of this study was to prospectively determine the relationship between skin closure and wound infection. One hundred fourteen consecutive patients (70 men and 44 women) undergoing bypass surgery with a groin incision (n = 173) were randomly assigned to skin closure with subcuticular Maxon, interrupted nylon, continuous nylon, or clips following a standard two-layer closure of subcutaneous tissue. Fourteen (12%) patients had diabetes and 50 (44%) had digital ulceration and gangrene. Aortofemoral bypass was performed in 25% of the patients and infrainguinal bypass in the remaining 75%. Perioperative wound cultures were obtained before closure. Wounds were inspected and cultures repeated on postoperative days 3, 5, 7, 10, and 14. Infection was defined as a positive culture. Groin wound infection occurred in 3% of the population and graft infection in 0.6%. The type of suture did not influence the incidence of infection. This study failed to demonstrate a significant difference in the incidence of wound infection with the use of different suture materials. We conclude that suture material should be selected on the basis of surgeon preference and costs.

Aged↗
PubMed1995

The introduction of laparoscopic cholecystectomy--audit of transition period with late follow-up.

The operative treatment of 356 consecutive patients with gallstone related disease who presented in the thirty months following the introduction of laparoscopic cholecystectomy was reviewed. A standard questionnaire, with emphasis on total hospital stay (including convalescence), late postoperative morbidity and time to return to work/full activity was sent to all patients. Two hundred and ninety-eight patients responded (83%). The median duration of follow-up was 19 months, (range 6-36 months). Patients who underwent laparoscopic cholecystectomy spent significantly less time in hospital post-operatively (median 3 days, interquartile range 2-4) than either those who required conversion to open cholecystectomy (median 7.5 days, interquartile range 5.5-10) or those who had planned open cholecystectomy (median 9.5 days, interquartile range 5-13), (p < 0.001, Kruskal-Wallis). Planned gall bladder extraction through the umbilical port site was associated with a significantly higher probability of wound infection compared with extraction through the epigastric port site (chi 2 = 4.977, P < 0.05). The median time to return to work/full activity was significantly shorter after laparoscopic cholecystectomy (median 21 days, interquartile range 14-42), than after open cholecystectomy (median 42 days, interquartile range 21-60) or following conversion to open cholecystectomy (median 56 days, interquartile range 35-60). We conclude that laparoscopic cholecystectomy requires a significantly shorter hospitalisation than open cholecystectomy and facilitates early return to work/full activity.

Cholecystectomy↗
PubMed1995

Repeated blood glucose measures using a novel portable glucose meter.

We describe the use of a novel portable blood glucose meter to repetitively and rapidly measure blood glucose levels in mice. We used this apparatus to replicate in the mouse, an insulin tolerance test (ITT) developed for humans. This test involves repeated glucose sampling (0, 1, 3, 5, 7, 10, 15, and 20 min) after an IV bolus of 0.4 IU/Kg of insulin. We first ran comparative tests with a conventional automated glucose analyser to assess the precision and reliability of the blood glucose meter for use in the mouse. High correlation were found between the two measures using either capillary or trunk whole blood. The variability of measurement over five consecutive determinations was about 3%. It was possible to take repetitive measures at about 70 s intervals.

Adult↗
PubMed1995

Unilateral breast masses in men over 40: a diagnostic dilemma.

BACKGROUND: Breast enlargement in men is a common condition with advancing age. The main problem in this age group is to differentiate gynecomastia or benign enlargement from carcinoma. PATIENTS AND METHODS: Over a 14-year period, 60 patients > or = 40 years old were operated on four unilateral breast masses (11 carcinoma, 49 gynecomastia) at the University College Hospital, Galway, Ireland. The medical records of these patients were reviewed and data were collected from patients' charts and histopathology records. RESULTS: Patients with carcinoma delayed significantly longer before presentation than patients with gynecomastia, a median of 33 versus 3.4 months, respectively. A lump was the presenting complaint in patients with carcinoma unless the disease was advanced. Patients with gynecomastia were more likely to present with pain; and the majority of these patients described tenderness on clinical examination. A history of carcinoma (18% and 0%) or a family history of breast carcinoma (36% and 14%) was more common in the patients with carcinoma than in those with gynecomastia, respectively (P < 0.05; P = NS, respectively). Histories of consuming alcohol and smoking cigarettes were more common in those with gynecomastia (67% and 43%) than in those with carcinoma (55% and 18%). A similar proportion of patients in both groups were taking drugs known or suspected to cause gynecomastia (29% and 27%). CONCLUSIONS: Carcinoma must be excluded in patients presenting with unilateral breast masses, particularly in those patients who present with painless masses. Clues to the diagnosis are provided by a history of carcinoma or a family history of breast carcinoma. A history of consumption of drugs known to cause gynecomastia should not influence the decision to perform a biopsy on unilateral breast masses in older men.

Adult↗
PubMed1995

Prospective evaluation of a composite scoring system for mammographically detected cytologically assessed impalpable breast abnormalities.

The aim of all breast screening programmes is a reduction in deaths from the disease. It is hoped that this can be achieved with minimal intervention in the patient cohort who do not have cancer. In this study we have assessed the efficacy of a combination of mammographic and cytological scoring systems in the evaluation of 208 women with screen-detected non-palpable breast lesions. All mammograms were scored 1-5 and those with a score of 3 or more required needle localization. A cytology score of 1 to 5 was generated for each patient according to a similar system and an aggregate score for each patient was achieved by the addition of the mammographic and cytology score. Ninety-three of the 208 patients had malignancy--the positive predictive value for mammography alone in this series was 45%. All 58 patients who had an aggregate score of 8 or greater had cancer. The 60 patients who had an aggregate score of 4 had benign disease on excision biopsy. We suggest that a 'wait and repeat mammogram' approach is appropriate in patients with grade 3 mammography and benign (grade 1) cytology. Patients with an intermediate aggregate score of 5-7 should have an excision biopsy and those with an aggregate score of 8 could have definitive surgery rather than excision biopsy. Application of this aggregate scoring technique would enhance the delivery of more appropriate surgery to a majority of patients with screen-detected breast abnormalities.

Biopsy↗
PubMed1995

An evaluation of preoperative CA 15-3 measurement in primary breast carcinoma.

In this study of 500 patients with breast carcinoma, we have prospectively assessed the role of preoperative CA 15-3 as a marker of disease burden over a 7 year period. CA 15-3 levels at presentation correlate with stage of disease, tumour size, lymph node status, the presence of metastases and lymphocyte infiltration into the tumour. CA 15-3 alone is not an independent prognostic indicator, although a serum level of > 40 U ml-1 has a positive predictive value of 83% for the presence of advanced disease. We recommend the routine use of this marker in the preoperative assessment of primary breast carcinoma.

Breast Neoplasms↗