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R Goldberg

Publications and source records attributed to R Goldberg.

At least 19 recordsLinked to original sources
PubMed2006

A randomised controlled trial evaluating the effects of two workstation interventions on upper body pain and incident musculoskeletal disorders among computer operators.

BACKGROUND: Call centre work with computers is associated with increased rates of upper body pain and musculoskeletal disorders. METHODS: This one year, randomised controlled intervention trial evaluated the effects of a wide forearm support surface and a trackball on upper body pain severity and incident musculoskeletal disorders among 182 call centre operators at a large healthcare company. Participants were randomised to receive (1) ergonomics training only, (2) training plus a trackball, (3) training plus a forearm support, or (4) training plus a trackball and forearm support. Outcome measures were weekly pain severity scores and diagnosis of incident musculoskeletal disorder in the upper extremities or the neck/shoulder region based on physical examination performed by a physician blinded to intervention. Analyses using Cox proportional hazard models and linear regression models adjusted for demographic factors, baseline pain levels, and psychosocial job factors. RESULTS: Post-intervention, 63 participants were diagnosed with one or more incident musculoskeletal disorders. Hazard rate ratios showed a protective effect of the armboard for neck/shoulder disorders (HR = 0.49, 95% CI 0.24 to 0.97) after adjusting for baseline pain levels and demographic and psychosocial factors. The armboard also significantly reduced neck/shoulder pain (p = 0.01) and right upper extremity pain (p = 0.002) in comparison to the control group. A return-on-investment model predicted a full return of armboard and installation costs within 10.6 months. CONCLUSION: Providing a large forearm support combined with ergonomic training is an effective intervention to prevent upper body musculoskeletal disorders and reduce upper body pain associated with computer work among call centre employees.

Adult↗
PubMed2005

Long-term survival of patients with resistant lymphoma treated with tandem stem cell transplant.

Dose-intensive chemotherapy with autologous stem cell support is commonly used in resistant/refractory cases of Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL). The purpose of this study was to evaluate the role of tandem transplantation in these patients. We used non cross-resistant conditioning regimens with thiotepa, mitoxantrone and carboplatin (TMJ) followed by ifosphamide, carboplatin and etoposide (ICE) with autologous stem cell rescue in an attempt to maximize dose intensity and achieve long-term remission. Seventy-six patients were included in this study. Twenty-nine patients with HD and 47 with NHL underwent autologous stem cell transplant using TMJ as the conditioning regimen for the first transplant. Of these, 49 patients proceeded to the second transplant using ICE as the conditioning regimen. In 57 patients, only peripheral blood cells were used and in 11 patients both bone marrow and peripheral stem cells were used. Twelve patients died due to treatment-related toxicity. On an intent to treat basis, 32.14% of patients with HD refractory to initial or subsequent therapy survived long term as opposed to 12.76% of patients with NHL. With a median follow-up of 83 months (range 25 - 110 months), the median disease-free survival of patients with HD was 7 months, as opposed to 2 months for patients with NHL. Multivariate analysis identified that patients with HD had a superior outcome if they were less than 35 years of age and did not have B symptoms. Dose-intensive chemotherapy with tandem transplantation is an option in patients with resistant/refractory lymphoma who have very limited treatment options and poor prognosis.

Adult↗
PubMed2005

Changes in mortality and morbidities among infants born at less than 25 weeks during the post-surfactant era.

OBJECTIVES: To compare mortality and death or major morbidity (DOMM) among infants <25 weeks estimated gestational age (EGA) born during two post-surfactant era time periods. STUDY DESIGN AND PATIENTS: Comparative cohort study of very low birthweight (501-1500 g) infants <25 weeks EGA in the NICHD Neonatal Research Network born during two post-surfactant era time periods (group I, 1991-1994, n=1408; group II, 1995-1998, n=1348). Perinatal and neonatal factors were compared, and group related mortality and DOMM risk were evaluated. RESULTS: Mortality was higher for group I (63.1% v 56.7%; p=0.0006). Antenatal steroids (ANS) and antenatal antibiotics (AABX), surfactant (p<0.0001), and bronchopulmonary dysplasia (p=0.0008) were more prevalent in group II. In a regression model that controlled for basic and delivery factors only, mortality risk was greater for group I than for group II (odds ratio (OR) 1.4, 95% confidence interval (CI) 1.2 to 1.7); the addition of AABX and surfactant, or ANS (OR 0.97, 95% CI 0.79 to 1.2) to the model appeared to account for this difference. There was no difference in DOMM (86.8% v 88.4%; p=0.2), but risk was lower for group I in regression models that included ANS (OR 0.70, 95% CI 0.52 to 0.94). CONCLUSION: Survival to discharge was more likely during the more recent period because of group differences in ANS, AABX, and surfactant. However, this treatment shift may reflect an overall more aggressive management approach. More consistent application of treatment has led to improving survival of <25 week EGA infants during the post-surfactant era, but possibly at the cost of greater risk of major in-hospital morbidities.

Analysis of Variance↗
PubMed2004

Differentiating thrombotic microangiopathies induced by severe hypertension from anemia and thrombocytopenia seen in thrombotic thrombocytopenia purpura.

Thrombotic microangiopathy (TMA) is a recognized complication of malignant hypertension (HTN). Such patients have blood pressures > or = 200/140 mmHg but the condition is defined by the presence of papilledema and is frequently complicated by acute renal failure. Here we report two patients with severe HTN (systolic > or = 180 mmHg or diastolic > or = 120 mmHg), TMA, thrombocytopenia, renal failure, and, in one case, neurological changes (4 of 5 manifestations of the TTP pentad). A 50-year-old male with HTN presented with blurred vision, dizziness, headache, confusion, renal failure, and a TMA (PLT = 39 x 10(9)/L and LD = 2,781 normal <600 U/L). On presentation, BP was 214/133 mmHg and an ophthalmic exam demonstrated no papilledema. With HTN control over 7 days, his platelet count rebounded (220 x 10(9)/L), LD declined (1,730 U/L), and mental status improved. A 60-year-old female with diabetes, HTN, Lupus erythematosus, mild chronic anemia, and thrombocytopenia presented with abdominal pain, shortness of breath, renal failure, and a TMA (PLT = 83 x 10(9)/L and LD = 2,929 U/L). Blood pressures were 180-210/89-111 mmHg and ophthalmic exam demonstrated no papilledema. With HTN control over 8 days, her platelet count rebounded (147 x 10(9)/L), and LD declined (1,624 U/L). Although in both cases a diagnosis of TTP was considered because of overlap with the classic diagnostic pentad, neither received plasmapheresis. TTP is a diagnosis of exclusion, where there is no other likely diagnosis to explain the TMA. In cases of severe HTN (with or without papilledema), the diagnosis of TTP should be held in abeyance until the effect of HTN control can be assessed.

Anemia↗
PubMed2004

Gender differences in TNF-alpha levels among obese vs nonobese Latino children.

OBJECTIVE: To examine the relationships between TNF-alpha, obesity, and insulin resistance among prepubescent children. DESIGN: Cross-sectional study. SETTING AND SUBJECTS: Data were collected from 112 nondiabetic Latino schoolchildren from public schools in three South Florida communities. Of the enrolled participants, 43.8% were obese (BMI 95th percentile) and 51.8% presented with a family history of type 2 diabetes mellitus (T2DM). With one exception, all demonstrated normal glucose tolerance. INTERVENTIONS: Plasma TNF-alpha levels were determined with enzyme-linked immunosorbance assay (ELISA). Homeostasis model assessment (HOMA-IR) was calculated as an index of insulin resistance. Mean levels of TNF-alpha among obese vs nonobese children were compared with a one-way analysis of variance with two groups, and the association between TNF-alpha and HOMA-IR was assessed with a Pearson's correlation. RESULTS: Higher circulating TNF-alpha levels were revealed among nonobese vs obese children. Nonobese girls demonstrated higher TNF-alpha levels than obese girls, whereas there were no significant differences for boys. There were no significant differences after stratifying for family history of T2DM. There was a modest relationship between increased TNF-alpha levels and decreased insulin resistance. CONCLUSIONS: The observed elevated circulating TNF-alpha concentrations among leaner participants may reflect an inflammatory process that has been associated with higher levels of physical fitness in both adults and prepubescent children. This effect may remain stronger for prepubescent girls, and the mechanism may be attenuated by the hormonal changes that occur with the onset of puberty.

Body Mass Index↗
PubMed2002

Impact of an ACE inhibitor and calcium antagonist on microalbuminuria and lipid subfractions in type 2 diabetes: a randomised, multi-centre pilot study.

BACKGROUND: Microalbuminuria (MA) is associated with increased cardiovascular risk and lipid abnormalities in people with type 2 diabetes. ACE inhibitors and calcium channel blockers (CCBs) reduce MA and are neutral on total cholesterol and triglycerides. The effect of ACE inhibitors and CCBs on lipid subfractions such as Lp(a), apolipoprotein (apo) A1, apo B, and others, however, is unclear. The current study tests the hypothesis that a fixed-dose combination of an ACE inhibitor, benazepril (B) with the dihydropyridine CCB, amlodipine (A), will further reduce arterial pressure and reduce atherogenic lipid fractions compared to either agent alone. DESIGN: A multicentre, randomised, open-label, parallel group design was used to study 27 participants with type 2 diabetes. Measurements for total cholesterol, high- and low-density lipoprotein (HDL and LDL), triglycerides, apo A1, apo B, Lp(a), MA, arterial pressure and creatinine clearance were obtained at baseline and at 12-week intervals during the 36 week study. RESULTS: Arterial pressure was significantly reduced at 36 weeks in all three groups (P = 0.0078 for A, P = 0.0039 for B, and P = 0.0313 for A+B). MA was lowered in all groups with relatively greater reductions in the B (P < 0.05) and A+B groups (P < 0.03) vs A. An increase in mean HDL-cholesterol from baseline was noted in the B and A+B groups; P < 0.05), but not in the A group. A trend was also observed between the rise in HDL-cholesterol and the reduction in MA in the B and A+B groups. Additionally, only the B group exhibited a decrease in the median value of Lp(a) (P < 0.05). CONCLUSION: These data support the concept that ACE inhibition with B reduces the atherogenic profile by decreasing Lp(a) and increasing HDL-cholesterol, the latter being correlated with reductions in MA. While A+B exhibited similar trends in lipid subfractions and MA as B, this group had the greatest reduction in systolic blood pressure of the three groups. Thus, use of A+B offers the benefits of a decreased atherogenic profile with a higher probably of achieving goal blood pressure as recommended by national guidelines.

Aged↗
PubMed2001

Phase I trial of sequential administration of raltitrexed (Tomudex) and 5-iodo-2'-deoxyuridine (IdUrd).

Raltitrexed (Tomudex) is a specific inhibitor of thymidylate synthase with clinical activity in colorectal cancer. The combination of raltitrexed and 5-iodo-2'-deoxyuridine (IdUrd, a cytotoxic pyrimidine analog) resulted in increased IdUrd incorporation into DNA and exhibited in vitro synergism against colon and bladder human carcinoma cell lines. We designed a phase I trial to determine the MTD, pharmacokinetics, and biologic effects of escalating doses of the combination of IdUrd given as a 24-hour infusion after a raltitrexed 15-minute infusion every three weeks. Thirty-four patients received 95 courses of raltitrexed and IdUrd at doses ranging from raltitrexed 1 mg/m2 and IdUrd 750 mg/m2 to raltitrexed 2.5 mg/m2 and IdUrd 10,400 mg/m2. The median number of cycles administered was 2 (range 1-10). Dose limiting hematologic toxicity occurred at doses of raltitrexed 2.5 mg/m2 and IdUrd 10,400 mg/m2. In addition, we determined the mean plasma concentrations C(SS) of IdUrd, the iodouracil level at 22 hours and the IdUrd clearance. Raltitrexed did not appear to affect the pharmacokinetics of IdUrd in the dose range tested. The recommended phase II dose is raltitrexed 2 mg/m2 and IdUrd 10,400 mg/m2 repeated every three weeks. Evidence of potential antitumor activity was observed: 1 patient (with colon cancer) had a partial response while 15 others had stable disease.

Adult↗
PubMed2001

Mutations in PTPN11, encoding the protein tyrosine phosphatase SHP-2, cause Noonan syndrome.

Noonan syndrome (MIM 163950) is an autosomal dominant disorder characterized by dysmorphic facial features, proportionate short stature and heart disease (most commonly pulmonic stenosis and hypertrophic cardiomyopathy). Webbed neck, chest deformity, cryptorchidism, mental retardation and bleeding diatheses also are frequently associated with this disease. This syndrome is relatively common, with an estimated incidence of 1 in 1,000-2,500 live births. It has been mapped to a 5-cM region (NS1) [corrected] on chromosome 12q24.1, and genetic heterogeneity has also been documented. Here we show that missense mutations in PTPN11 (MIM 176876)-a gene encoding the nonreceptor protein tyrosine phosphatase SHP-2, which contains two Src homology 2 (SH2) domains-cause Noonan syndrome and account for more than 50% of the cases that we examined. All PTPN11 missense mutations cluster in interacting portions of the amino N-SH2 domain and the phosphotyrosine phosphatase domains, which are involved in switching the protein between its inactive and active conformations. An energetics-based structural analysis of two N-SH2 mutants indicates that in these mutants there may be a significant shift of the equilibrium favoring the active conformation. This implies that they are gain-of-function changes and that the pathogenesis of Noonan syndrome arises from excessive SHP-2 activity.

Chromosomes, Human, Pair 12↗
PubMed2001

Prospective randomized trial of polyglactin 910 mesh to prevent recurrence of cystoceles and rectoceles.

OBJECTIVE: Our aim was to evaluate the efficacy of polyglactin 910 mesh in preventing recurrent cystoceles and rectoceles. STUDY DESIGN: In a prospective, randomized, controlled trial, patients undergoing vaginal reconstructive surgery with cystoceles to the hymenal ring and beyond were randomly selected to undergo anterior and posterior colporrhaphy with or without polyglactin 910 mesh reinforcement. Results were evaluated preoperatively and at 2, 6, 12, and 52 weeks postoperatively. RESULTS: A total of 161 women were randomly selected for this study. One woman was excluded at the time of surgery, and 17 women were lost to follow-up. Eighty women received mesh, and 80 did not. Both groups were found to be equivalent with respect to age, parity, concomitant surgery, and menopausal and hormone replacement status. Preoperatively 49 women had a central cystocele to the hymenal ring and 111 women had cystoceles beyond the introitus; 91 women had a rectocele to the mid-vaginal plane, 31 to the hymenal ring, and 22 beyond the introitus. After 1 year, 30 (43%) of 70 subjects without mesh and 18 (25%) of 73 subjects with mesh had recurrent cystoceles beyond the mid-vaginal plane (P =.02). Eight women without mesh and 2 women with mesh had recurrent cystoceles to the hymenal ring (P =.04). No recurrent cystoceles beyond the hymenal ring occurred in either group. Multivariate logistic regression analysis showed concurrent slings to be associated with significantly fewer recurrent cystoceles (odds ratio, 0.32; P =.005), whereas the presence of mesh remained significantly predictive of fewer cystocele recurrences in this analysis. Thirteen recurrent rectoceles were noted 1 year postoperatively, with no differences between groups. CONCLUSION: Polyglactin 910 mesh was found to be useful in the prevention of recurrent cystoceles.

Aged↗
PubMed2001

Do clerkship experiences affect medical students' attitudes toward chronically ill patients?

PURPOSE: To measure changes in medical students' attitudes toward chronically ill patients, and to identify experiences, specifically during clerkships, that contributed to students' attitudes. METHOD: A cohort of students from five U.S. medical schools voluntarily participated in three surveys longitudinally administered before and after required clinical rotations. The first two questionnaires were identical and asked for demographic information and pre-matriculation experiences with chronically ill patients. The third was modified to include questions about clinical experiences with chronically ill patients. Responses from the first and third questionnaires were linked for analysis. RESULTS: A total of 502 of 695 students (69%) completed both the first and the third questionnaires. Many students (36%) had had pre-matriculation experiences with chronic illness. After clinical training, 25% of the respondents stated that they would seek another career specialty if the incidence of chronically ill patients increased in their chosen field, compared with the 9% who responded so before clinical training (p <.001). While 73% of the students had favorable perceptions toward chronically ill patients, and 91% felt involved in care, significantly fewer students (p <.01) had had positive patient care experiences when working with residents (57%) and attendings (59%). Gender, age, prior experiences, and school site were not associated with attitudinal changes. CONCLUSION: Students begin medical school with positive attitudes toward caring for chronically ill patients, but this perception depreciates with clinical experience, which may affect specialty decisions. Contributing factors may include adequate role modeling by residents and attendings and a perceived discrepancy in the quality of care patients receive.

Adult↗
PubMed2001

The impact of health status on work, symptoms, and functional outcomes in severe mental illness.

This study evaluated the relationships between self-ratings of physical role functioning and general health, two components of the MOS SF-36, and a variety of demographic, quality of life, clinical, functional, and attitudinal variables in a cohort of adults living with severe and persistent mental illness (SPMI). We hypothesized that poorer self-perceptions of physical functioning and general health would be significantly related to more severe symptoms and poorer functioning and quality of life. Study subjects were 218 adults with SPMI enrolled in a randomized controlled trial comparing two vocational interventions for persons who were unemployed. Hierarchical regression analysis was used to determine whether psychiatric symptoms, poorer self-perceptions of role limitations due to physical health problems and overall general health independently contributed to more severe symptoms and poorer functioning and quality of life. Psychiatric symptoms were inversely related to size of social network and satisfaction with safety. Increased role limitations were associated with reduced medication compliance, general life satisfaction, and satisfaction with health, daily activities, and safety. Reduced general health was significantly associated with reduced work motivation, self-esteem, current inability to work, self-report of functioning, and almost all subjective life satisfaction domains. Within this group of people with severe mental illness, psychiatric symptoms were minimally associated with outcomes. Physical role limitations contributed more, and an integrated global measure of overall health perception was most important. If we are to help persons with severe mental illness maximize their quality of life and functioning, our clinical interventions should employ an approach that appreciates and recognizes the importance of the patients' experience of a holistic and integrated experience of health.

Adult↗
PubMed2000

Control of Mung bean pectinmethylesterase isoform activities. Influence of pH and carboxyl group distribution along the pectic chains.

Well-characterized pectin samples with a wide range of degrees of esterification (39-74%) were incubated with the solubilized pure alpha and gamma isoforms of pectinmethylesterase, from mung bean hypocotyl (Vigna radiata). Enzyme activity was determined at regular intervals along the deesterification pathway at pH 5.6 and pH 7.6. It has been demonstrated that the distribution of the carboxyl units along the pectin backbone controls the activity of the cell wall pectinmethylesterases to a much greater extent than the methylation degree, with a random distribution leading to the strongest activity. Polygalacturonic acid was shown to be a competitive inhibitor of the alpha isoform activity at pH 5.6 and to inhibit the gamma isoform activity at both pH 5.6 and pH 7.6. Under these conditions, the drop in enzyme activity was shown to be correlated to the formation of deesterified blocks of 19 +/- 1 galacturonic acid residues through simulations of the enzymatic digestion according to the mechanisms established previously (Catoire, L., Pierron, M., Morvan, C., Herve du Penhoat, C., and Goldberg, R. (1998) J. Biol. Chem. 273, 33150-33156). However, even in the absence of inhibition by the reaction product, activity dropped to negligible levels long before the substrate had been totally deesterified. Comparison of alpha and gamma isoform cDNAs suggests that the N-terminal region of catalytic domains might explain their subtle differences in activity revealed in this study. The role of pectinmethylesterase in the cell wall stiffening process along the growth gradient is discussed.

Amino Acid Sequence↗
PubMed2000

AT-rich palindromes mediate the constitutional t(11;22) translocation.

The constitutional t(11;22) translocation is the only known recurrent non-Robertsonian translocation in humans. Offspring are susceptible to der(22) syndrome, a severe congenital anomaly disorder caused by 3&rcolon;1 meiotic nondisjunction events. We previously localized the t(11;22) translocation breakpoint to a region on 22q11 within a low-copy repeat termed "LCR22" and within an AT-rich repeat on 11q23. The LCR22s are implicated in mediating different rearrangements on 22q11, leading to velocardiofacial syndrome/DiGeorge syndrome and cat-eye syndrome by homologous recombination mechanisms. The LCR22s contain AT-rich repetitive sequences, suggesting that such repeats may mediate the t(11;22) translocation. To determine the molecular basis of the translocation, we cloned and sequenced the t(11;22) breakpoint in the derivative 11 and 22 chromosomes in 13 unrelated carriers, including two de novo cases and der(22) syndrome offspring. We found that, in all cases examined, the reciprocal exchange occurred between similar AT-rich repeats on both chromosomes 11q23 and 22q11. To understand the mechanism, we examined the sequence of the breakpoint intervals in the derivative chromosomes and compared this with the deduced normal chromosomal sequence. A palindromic AT-rich sequence with a near-perfect hairpin could form, by intrastrand base-pairing, on the parental chromosomes. The sequence of the breakpoint junction in both derivatives indicates that the exchange events occurred at the center of symmetry of the palindromes, and this resulted in small, overlapping staggered deletions in this region among the different carriers. On the basis of previous studies performed in diverse organisms, we hypothesize that double-strand breaks may occur in the center of the palindrome, the tip of the putative hairpin, leading to illegitimate recombination events between similar AT-rich sequences on chromosomes 11 and 22, resulting in deletions and loss of the palindrome, which then could stabilize the DNA structure.

AT Rich Sequence↗
PubMed2000

Discrepancies in the use of medications: their extent and predictors in an outpatient practice.

BACKGROUND: Misuse of medications is a major cause of morbidity and mortality. Few studies have examined the frequency of, and factors associated with, discrepancies between what doctors prescribe and what patients take in actual practice. PATIENTS AND METHODS: Patients' medication bottles and their reported use of medications were compared with physicians' records of outpatients seen between November 1997 and February 1998 in a private practice affiliated with an academic medical center in Boston, Mass. Three hundred twelve patients from the practices of 5 cardiologists and 2 internists who were returning for their routine follow-up visits were included. MAIN OUTCOME MEASURE: The presence of discrepancies based on comparing medication bottles with medical records. RESULTS: Discrepancies were present in 239 patients (76%). The 545 discrepancies in these patients were the result of patients taking medications that were not recorded (n = 278 [51%]); patients not taking a recorded medication (n = 158 [29%]); and differences in dosage (n = 109 [20%]). Overall, discrepancies were randomly distributed among different drugs and discrepancy types with no discernible pattern. On multivariate analysis, patient age and number of recorded medications were the 2 most significant predictors of medication discrepancy. CONCLUSIONS: Discrepancies among recorded and reported medications were common and involved all classes of medications, including cardiac and prescription drugs. Older age and polypharmacy were the most significant correlates of discrepancy. The pervasiveness of discrepancies can have significant health care implications, and action is urgently needed to address their causes. Such action would likely have a positive impact on patient care.

Adult↗
PubMed2000

Demographic, belief, and situational factors influencing the decision to utilize emergency medical services among chest pain patients. Rapid Early Action for Coronary Treatment (REACT) study.

BACKGROUND: Empirical evidence suggests that people value emergency medical services (EMS) but that they may not use the service when experiencing chest pain. This study evaluates this phenomenon and the factors associated with the failure to use EMS during a potential cardiac event. METHODS AND RESULTS: Baseline data were gathered from a randomized, controlled community trial (REACT) that was conducted in 20 US communities. A random-digit-dial survey documented bystander intentions to use EMS for cardiac symptoms in each community. An emergency department surveillance system documented the mode of transport among chest pain patients in each community and collected ancillary data, including situational factors surrounding the chest pain event. Logistic regression identified factors associated with failure to use EMS. A total of 962 community members responded to the phone survey, and data were collected on 875 chest pain emergency department arrivals. The mean proportion of community members intending to use EMS during a witnessed cardiac event was 89%; the mean proportion of patients observed using the service was 23%, with significant geographic differences (range, 10% to 48% use). After controlling for covariates, non-EMS users were more likely to try antacids/aspirin and call a doctor and were less likely to subscribe to (or participate in) an EMS prepayment plan. CONCLUSIONS: The results of this study indicate that indecision, self-treatment, physician contact, and financial concerns may undermine a chest pain patient's intention to use EMS.

Adult↗
PubMed2000

Estuarine and habitat-related differences in growth rates of young-of-the-year winter flounder (Pseudopleuronectes americanus) and tautog (Tautoga onitis) in three northeastern US estuaries.

Instantaneous growth rates of young-of-the-year winter flounder Pseudopleuronectes americanus (Walbaum) (12.0-60.4 mm standard length, SL) and tautog Tautoga onitis (Linnaeus) (21.4-73.8 mm total length, TL) from three estuarine systems in New Jersey (Great Bay-Little Egg Harbor and Navesink River) and Connecticut (Hammonasset River) were used in an attempt to assess the relative quality of selected nominal habitats. A series of short-term field caging experiments were conducted during 1994 and 1995 in: macroalgae (primarily, Ulva lactuca), eelgrass (Zostera marina), unvegetated areas adjacent to macroalgae and eelgrass and tidal creeks in Spartina dominated marsh. Growth rates varied with habitat, estuary and year. Comparisons across nominal habitats within and among estuaries did not show any one habitat with consistently higher growth, and growth was relatively independent of whether a habitat was vegetated or adjacent to vegetation. The growth rates of winter flounder and tautog from the Hammonasset River were not different among habitats in either year of the study. In the Great Bay-Little Egg Harbor, both winter flounder and tautog had higher growth rates in macroalgae with growth in eelgrass varying significantly between years. Conversely, in the Navesink River both species had higher growth rates in eelgrass. Environmental changes associated with temperature and dissolved oxygen appeared to influence growth rates. Winter flounder growth rate and survival was depressed in tidal marsh creeks in the three estuaries and in vegetated macroalgae habitats in the Navesink River where dissolved oxygen levels were often very low (<2 mgl(-1)) for extended periods. In summary, the growth rates of the young-of-the-year of these two species varied temporally and were dependent on the interaction of both the specific estuary and habitat in which the experiments took place. Further, habitat quality, as defined by relative growth rate, was difficult to evaluate because it can be variable and nominal habitat designations are often not sufficient to define the boundaries of a species habitat requirements.

Journal Article↗
PubMed2000

Differential localization of arabinan and galactan side chains of rhamnogalacturonan 1 in cambial derivatives.

The development of pectin structural features during the differentiation of cambial derivatives was investigated in aspen (Populus tremula L. x P. tremuloides Michx.) using biochemical and immunocytochemical methods. Comparisons were also made between active and resting tissues. Active tissues, in particular cambial cells and phloem derivatives, were characterized by a high pectin content. Use of antibodies raised against arabinan side chains of rhamnogalacturonan 1 (LM6), as well as biochemical analysis, revealed an obvious decrease from the cortex to the differentiating xylem. Galactan side chains, detected with LM5 antibodies, were present mainly in the cambial zone and enlarging xylem cells. In contrast, they were totally absent from sieve-tube cell walls. Image analysis of LM5 immunogold labelling in the cambial zone showed a clustered distribution of galactan epitopes in the radial walls, a distribution which might result from the association of two different periodic processes, namely the exocytosis of galactan and wall expansion. Cessation of cambial activity was characterized by cell wall thickening accompanied by a sharp decrease in the relative amount of pectin and a lowering of the degree of methylesterification. The data provide evidence that the walls of phloem and xylem cells differ in their pectin composition even at a very early stage of commitment. These differences offer useful tools for identifying the initial cells among their immediate neighbours.

Cell Wall↗