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Biomedical subjects

D Rabin

Publications and source records attributed to D Rabin.

At least 19 recordsLinked to original sources
PubMed2001

Repeat cerebrospinal fluid shunt infection in children.

BACKGROUND: In this study, we investigated the treatment of cerebrospinal fluid (CSF) shunt infection and the risk factors for repeat shunt infection (RSI) in a cohort of children treated at the Hospital for Sick Children, Toronto, Canada. METHODS: Between 1996 and 2000, a total of 51 children were identified with shunt infection (mean age 5.8 years). The medical records of these children were reviewed to identify cases of RSI within 6 months of the initial shunt infection (ISI). RESULTS: In the 51 ISIs, the infecting organisms were coagulase-negative Staphylococcus (43.1%), Staphylococcus aureus (37.3%) and others (19.6%). The initial mode of treatment of the shunt infection was using an external ventricular drain (EVD) with removal of the shunt apparatus (54.9%), externalization of the shunt (37.3%) or shunt removal only (7.8%). The mean number of days of external CSF drainage (either EVD or externalized shunt) was 11.2 days. Ten patients (19.6%) developed RSI. The actuarial risk of RSI plateaued after 90 days at 24.4%. The following variables were tested as risk factors for RSI using survival analysis, although none reached statistical significance: initial organism (p = 0.09), age (p = 0.42), etiology of hydrocephalus (p = 0.45), number of days of CSF drainage (p = 0.45), type of surgical treatment of the ISI (p = 0.58) and the presence of bacteriologically positive CSF at ISI (p = 0.85). CONCLUSIONS: The risk of RSI is substantial and greater effort needs to be directed towards understanding the risk factors. Such studies will need a greater sample size in order to obtain sufficient statistical power.

Adolescent↗
PubMed2000

Posthospitalization home health care use and changes in functional status in a Medicare population.

OBJECTIVE: The objective of this work was to estimate the effect of Medicare beneficiaries' use of home health care (HHC) for 6 months after hospital discharge on the change in functional status over a 1-year period beginning before hospitalization. DATA SOURCES AND STUDY SETTING: Data came from the Medicare Current Beneficiary Survey, which is a nationally representative sample of Medicare beneficiaries, in-person interview data, and Medicare claims for 1991 through 1994 for 2,127 nondisabled, community-dwelling, elderly Medicare beneficiaries who were hospitalized within 6 months of their annual in-person interviews. STUDY DESIGN: Econometric estimation with the instrumental variable method was used to correct for observational data bias, ie, the nonrandom allocation of discharged beneficiaries to the use of posthospitalization HHC. The analysis estimates a first-stage model of HHC use from which an instrumental variable estimate is constructed to estimate the effect on change in functional status. PRINCIPAL FINDINGS: The instrumental variable estimates suggest that HHC users experienced greater improvements in functional status than nonusers as measured by the change in a continuous scale based on the number and mix of activities of daily living and instrumental activities of daily living before and after hospitalization. The estimated improvement in functional status could be as large as 13% for a 10% increase in HHC use. In contrast, estimation with the observational data on HHC use implies that HHC users had poorer health outcomes. CONCLUSIONS: Adjusting for potential observational data bias is critical to obtaining estimates of the relationship between the use of posthospitalization HHC and the change in health before and after hospitalization. After adjustment, the results suggest that efforts to constrain Medicare's spending for HHC, as required by the Balanced Budget Act of 1997, may lead to poorer health outcomes for some beneficiaries.

Activities of Daily Living↗
PubMed1996

The maternal hypothalamic-pituitary-adrenal axis in the third trimester of human pregnancy.

OBJECTIVE: The third trimester of pregnancy is characterized by a mildly hyperactive hypothalamic-pituitary-adrenal (HPA) axis, possibly driven by elevated circulating levels of corticotrophin releasing hormone (CRH) of placental origin. In-vitro studies have demonstrated that glucocorticoids and oestrogen stimulate while progesterone inhibits the expression of CRH mRNA and/or protein, suggesting that several potential interactions between the placenta and the HPA axis may exist. DESIGN AND PATIENTS: To investigate the detailed pattern of circulating immunoreactive (ir) CRH, ACTH, cortisol, oestradiol and progesterone during the third trimester of pregnancy, plasma samples were drawn serially every 30 minutes from 22 healthy pregnant women (age 32.0 +/- 1.1 years, mean +/- SE) between the 34th and 36th week of gestation. Ten women had plasma samples drawn between 0800 h and 2000 h (daytime group), and 12 between 2000 h and 0800 h (night-time group). The hormone concentrations obtained were analysed for pulsatility by the Detect program, for detection of circadian rhythmicity by comparison between the first and second 6-hour periods within each group by Student's t-test, and for time-dependent correlations by cross-correlation analysis. RESULTS: All five hormones were secreted in a pulsatile fashion. There was no apparent circadian rhythm of CRH or oestradiol secretion, whereas there was a clear circadian rhythm in plasma ACTH, cortisol and progesterone secretion, with the latter in reverse phase (P < 0.05). No significant correlations were observed between CRH and ACTH, whereas, as expected, ACTH and cortisol concentrations were strongly correlated with each other over time (r = 0.32 and 0.70 at lag time 30 minutes for the daytime and night-time groups, respectively), with ACTH leading cortisol. A weak positive correlation was observed between CRH and cortisol concentrations for the night-time group at lag time 0 minute, suggesting that the latter may have a positive effect on the former in vivo. CONCLUSIONS: These data suggest that placental CRH, although pulsatile, drives quantitatively the maternal HPA axis in the third trimester of pregnancy in a non-circadian, non-pulsatile fashion. The maternal HPA axis is probably driven in a circadian and pulsatile fashion by another major ACTH secretagogue, most likely AVP of parvocellular paraventricular nucleus origin.

Adrenocorticotropic Hormone↗
PubMed1996

Presence of immunoreactive corticotropin-releasing hormone in human endometrium.

Immunoreactive CRH (IrCRH) is produced locally in experimentally induced and spontaneous inflammation. Where it exerts autocrine or paracrine proinflammatory effects. In addition, CRH is secreted by the human placenta, rat Leydig cells, and rat and human ovaries, where it may participate in the inflammatory processes of ovulation and luteolysis, and/or the regulation of steroidogenesis. Finally, CRH is secreted in vitro by cultured human epithelial and decidualized stromal endometrial cells. To investigate the presence of CRH in human endometrium in vivo, we examined this tissue immunohistochemically and by extraction/RIA using a polyclonal, highly specific antirat/human CRH antibody. Endometrial biopsies from 33 women, aged 23-43 yr (median age, 33.5 yr), were performed by linear endometrial curettage for diagnostic purposes at different stages of the cycle. Intense IrCRH staining was localized in the cytoplasm of cells of the endometrial glands in all samples examined. IrCRH was also found in endometrial stromal cells exhibiting decidual reaction and in local immune accessory cells. The mobility of the endometrial IrCRH molecule was similar to that of r/hCRH in reverse phase high pressure liquid chromatography. The presence of CRH in the endometrium, and more specifically in the glandular epithelium during the proliferative and secretory phases of the menstrual cycle together with its known proinflammatory properties, suggest that this neuropeptide might participate in the inflammatory-like phenomena of endometrial physiology, such as menstrual shedding, surface epithelium repair, and/or implantation of the blastocyst. The presence of CRH in decidualized stromal cells is in accordance with its previously reported production by in vitro decidualized cultured endometrial stromal cells as well as by the placental decidua.

Adult↗
PubMed1996

Hypothalamic corticotropin-releasing hormone suppression during the postpartum period: implications for the increase in psychiatric manifestations at this time.

The third trimester of human pregnancy is characterized by a hyperactive hypothalamic-pituitary-adrenal axis, possibly driven by progressively increasing circulating levels of placental CRH and gradually decreasing levels of CRH-binding protein. The postpartum period, on the other hand, is characterized by an increased vulnerability to psychiatric manifestations (postpartum "blues," depression, and psychosis), a phenomenon compatible with suppressed hypothalamic CRH secretion. To investigate the hypothesis that the postpartum period is associated with suppression of hypothalamic CRH secretion, we studied prospectively 17 healthy euthymic women (mean +/- SE age, 32.0 +/- 1.1 yr) with no prior history of depression, starting at the 20th week of gestation. Psychometric testing was performed monthly during pregnancy and postpartum on day 2 and weeks 2, 3, 6, 8, 12, 16, and 20, whereas serial ovine (o) CRH tests were performed postpartum at 3, 6, and 12 weeks. While pregnant, all 17 subjects remained euthymic; in the postpartum period, 7 women developed the "blues," and 1 developed depression. Overall, the mean plasma ACTH response to an iv bolus of 1 microgram/kg oCRH was markedly blunted at 3 and 6 weeks, but normal at 12 weeks postpartum, whereas the mean plasma cortisol response was at the upper limit of normal at all 3 times. These data are compatible with a suppressed hypothalamic CRH neuron that gradually returns to normal while hypertropic adrenal cortexes are progressively down-sizing. When the postpartum ACTH responses to oCRH were analyzed separately for the euthymic women and the women who had the "blues" or depression, the blunting of ACTH was significantly more severe and long lasting in the latter group; this was observed at all 3 times of testing. We conclude that there is central suppression of hypothalamic CRH secretion in the postpartum, which might explain the increased vulnerability to the affective disorders observed during this period. The suppressed ACTH response to oCRH might serve as a biochemical marker of the postpartum "blues" or depression.

Adrenocorticotropic Hormone↗
PubMed1995

The bubble test: a new tool to improve the diagnosis of endometriosis.

The objective of this study was to determine the clinical sensitivity and specificity of a bubbling phenomenon, including peritoneal surfaces, as a diagnostic test for endometriosis during laparoscopy. A prospectively controlled study of women with infertility of at least 1 year duration, who underwent laparoscopy, was conducted at a medical school-affiliated private infertility centre and research foundation. The study included 48 prospectively enrolled female infertility patients who underwent laparoscopy. Of these, 32 were found to suffer from endometriosis (group A) and 16 control patients did not show any evidence of disease (group B). The study involved the irrigation of the posterior cul-de-sac with short bursts of either saline or lactated Ringer's solution, utilizing a standard laparoscopic aspiration/irrigation system, and the subsequent observation for an excessive soap-like bubbling phenomenon (positive bubble test) in association with endometriosis. All 32 endometriosis patients (group A) demonstrated a positive bubble test. In contrast, only two of the 16 control patients (group B) were positive (P = 0.00242, Fisher's exact test; odds ratio, 8.000). A positive bubble test during laparoscopy was thus 100% sensitive and 88% specific for the diagnosis of endometriosis by laparoscopy, resulting in positive and negative predictive values of 94 and 100% respectively. Since the literature provides considerable evidence that the diagnosis of endometriosis during laparoscopy is frequently missed, a positive bubble test during laparoscopy therefore may be considered a reason to search further (possibly with biopsies) for endometriosis in the absence of obviously visible disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Ascitic Fluid↗
PubMed1994

Digital rectal examination, serum prostate specific antigen, and prostatic ultrasound: how effective is this diagnostic triad?

Ninety-nine of 105 consecutive men who underwent transrectal prostatic ultrasound (TRUS) at Highland Park Hospital had the results correlated with digital rectal examination (DRE), serum prostate specific antigen (PSA), and biopsy results. Ninety-six cases had evaluable ultrasound studies. Thirty-two of the 99 who underwent biopsy had primary carcinoma of the prostate. Prostate volume, predicted PSA, a ratio of observed/predicted PSA, and Gleason score were examined. There was no correlation between age and prostate volume, volume and the presence of carcinoma, or PSA and Gleason score. Thirty-one point six percent of the abnormal DREs, 36.6% of the abnormal TRUSs, and 40.6% of the elevated PSAs occurred in men with prostatic carcinoma (PCa). If PSA was normal (less than or equal to 4.0 ng/ml) and either DRE or TRUS was abnormal, then the risk of carcinoma was 2.9%. If PSA was elevated, regardless of the other two tests, the risk of finding PCa was at least 38%. If all three tests were abnormal, the risk of carcinoma was 38% in our series and 68% in a meta-analysis. Many men with PSA values between 4 and 10 ng/ml have benign biopsies. However, close future follow-up with consideration of repeat biopsy should be strongly considered.

Aged↗
PubMed1994

Laparoscopic removal of twin cornual pregnancy after in vitro fertilization.

The laparoscopic management of tubal pregnancies by salpingostomy has become a clinical standard of care (5). Those surgeries usually are performed for tubal pregnancies that are located distally to the cornua and the intramural piece of the tube. We previously reported on the conservative surgical management of interstitial pregnancies (3). To our knowledge, cornual pregnancies have never before been approached laparoscopically. Such a surgical approach is reported here, involving a twin gestation in the left uterine cornua conceived by IVF in a women with bilaterally absent tubes.

Adult↗
PubMed1991

Corticotropin-releasing hormone is not the sole factor mediating exercise-induced adrenocorticotropin release in humans.

To determine whether CRH is the sole mediator of ACTH release during exercise, five men and five women were given, in a subject-blinded random manner at separate visits, both a 6-h infusion of ovine CRH (1 microgram/kg.h) and a saline infusion as a placebo. After the fourth hour of each infusion, when plasma concentrations of ovine CRH were sufficiently elevated to saturate the capacity of the corticotroph to respond further to CRH, each subject completed a high intensity intermittent run. Plasma ACTH and cortisol levels increased significantly during the CRH infusion from 4.6 +/- 0.8 (mean +/- SE) to 8.6 +/- 1.6 pmol/L and from 361 +/- 39 to 662 +/- 70 nmol/L, respectively (P less than 0.05). Despite elevated preexercise cortisol levels during the CRH infusion, plasma ACTH rose to 32.0 +/- 8.5 pmol/L after exercise. During the saline infusion, plasma ACTH rose from 3.4 +/- 0.6 pmol/L before exercise to 18.1 +/- 4.2 after exercise. Time-integrated responses for postexercise values of ACTH and cortisol were higher during the CRH infusion than during the saline infusion (P less than 0.05). No significant exercise-induced differences in heart rate or plasma concentrations of lactate, epinephrine, and norepinephrine were observed between the two tests. The findings suggest that some factor(s) in addition to CRH causes ACTH release during exercise. Vasopressin, produced by the magnocellular and/or parvocellular neurons of the hypothalamus, is a likely candidate.

Adrenocorticotropic Hormone↗
PubMed1988

Human placenta and the hypothalamic-pituitary-adrenal axis.

Maternal plasma bound and free cortisol rises during pregnancy, while maternal plasma IR-ACTH is initially low but soon rises inspite of the further increase of plasma free cortisol. This rise of plasma ACTH during pregnancy, can not be attributed to changes of plasma levels of estrogens or progesterone. It is possible that the human placenta is responsible for the rise in maternal plasma ACTH during pregnancy. There are two possible mechanisms by which this effect could occur: 1) by the placental secretion of CRH into the maternal circulation, which stimulates the maternal pituitary to secrete ACTH, and 2) the secretion of placental POMC-derived peptides. Recent data indicate that the human placenta is capable of both of these actions: A) The POMC and CRH genes are expressed in human placenta; B) the human term placenta is able to secrete both CRH and POMC-derived peptides in vitro; C) the CRH present in the plasma of pregnant women is bioactive and in sufficient levels to be effective on maternal pituitary; D) synthetic hCRH can stimulate the release of placental POMC peptides in vitro. We conclude that the human placenta may be a modulator of the HPA axis during pregnancy in a number of possible ways. Additional experimental work should clarify the intriguing interaction between the HPA axis and the human placenta during pregnancy, labor and delivery.

Adrenocorticotropic Hormone↗
PubMed1988

Increased pro-opiomelanocortin-derived peptide release in myotonic dystrophy.

The response of plasma immunoreactive (IR)-ACTH, IR-beta-endorphin (beta-END) and IR-cortisol to insulin-induced hypoglycaemia, an acute stimulus to the pituitary corticotrophs through the central nervous system, and to synthetic ovine corticotrophin-releasing hormone (CRH), a direct corticotroph stimulator, were studied in normal males and males with myotonic dystrophy. Myotonics had an increased IR-ACTH and IR-beta-END response to hypoglycaemia and an increased IR-ACTH response to CRH compared with normals. Plasma IR-cortisol response were not different in either group of subjects to both stimuli. This neuroendocrine abnormality in myotonic dystrophy may represent a manifestation of the purported specific cell membrane defect underlying the disease. This is the first report of an abnormality in proopiomelanocortin peptide release in myotonic dystrophy.

Adolescent↗
PubMed1987

A simple DNA diagnostic method for human genetic disorders.

A fast, reliable, and simple technique for detecting point mutations in unfractionated human DNA has been developed. Oligonucleotide probes complementary to either sickle- or normal beta-globin DNA are labeled by primer extension and hybridized to DNA applied to nitrocellulose paper in a dot-blot format. A short hybridization time (about 1 h) and low probe concentration (about 1 nM) yield low background and high specificity. Double-blind trials show 100% agreement with restriction fragment length polymorphism (RFLP) analysis of DNA from normal, sickle, and heterozygous subjects.

Anemia, Sickle Cell↗
PubMed1986

Simultaneous panic and depressive disorders: clinical and sleep EEG correlates.

Panic and depressive symptoms occur simultaneously in many depressed patients. To study the frequency of this association and to determine whether patients with simultaneous panic and major depression differed from those with only major depressive disorder (MDD) in clinical features and in sleep electroencephalographic (EEG) variables, we evaluated a total sample of 336 patients with MDD. Fifty-eight (17%) had both panic and MDD; 50 had complete data and were matched for age and severity of illness with other patients having only MDD. Patients with simultaneous panic and depression had significantly higher ratings for psychic and somatic anxiety, and rapid eye movement (REM) latencies approximating normal values. Patients with only MDD (without panic disorder) rated significantly higher in guilt feelings and had shorter REM latencies. Our results suggest that the simultaneous occurrence of panic and depression is relatively frequent, is accompanied by differences in sleep EEG variables, and may have implications for treatment.

Adult↗