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Biomedical subjects

P Gold

Publications and source records attributed to P Gold.

At least 19 recordsLinked to original sources
PubMed2006

Vasopressin 1a receptor knockout mice have a subtle olfactory deficit but normal aggression.

Two receptors for vasopressin (Avp) are expressed in the brain, the Avp 1a receptor (Avpr1a) and the Avp 1b receptor (Avpr1b). To investigate the role of Avpr1a in behaviors in mice more extensively, we generated a line of mice lacking a functional Avpr1a (knockout, Avpr1a(-/-)). We first performed a baseline phenotypic screen of the Avpr1a knockouts followed by a more detailed analysis of their circadian rhythms and olfactory function. When free-running in constant darkness, the Avpr1a(-/-) mice have a longer circadian tau than the wild types. There are also subtle olfactory deficits in Avpr1a(-/-) mice as measured in an olfactory habituation/dishabituation test and in the discrimination of female urine from male urine using an operant testing paradigm. An extensive body of research has shown that manipulation of the Avpr1a alters behavior, including aggression and social recognition. Therefore, we expected profound behavioral deficits in mice lacking the Avpr1a gene. Contrary to our expectations, social aggression, anxiety-like behavior and social recognition are unaffected in this line of Avpr1a knockout mice. These data suggest either that the Avpr1a is not as critical as we thought for social behavior in mice or, more likely, that the neural circuitry underlying aggression and other social behaviors compensates for the life-long loss of the Avpr1a. However, the olfactory deficits observed in the Avpr1a(-/-) mice suggest that Avp and Avpr1a drugs may affect behavior, in part, by modulation of chemosensory systems.

Aggression↗
PubMed2001

Influence of preassay and sequence variations on viral load determination by a multiplex real-time reverse transcriptase-polymerase chain reaction for feline immunodeficiency virus.

Determination of retroviral load is an important tool in the investigation of the success of therapeutic or vaccination trials in patients infected with lentiviruses such as HIV, or with their simian (SIV) or feline (FIV) counterparts. We have developed an one-tube quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay based on the ABI Prism 7700 Sequence Detection System (TaqMan) to quantify the viral load of FIV-infected cats. Two different primer/probe systems were designed to detect a broad range of clade A FIV isolates. Both systems are characterized by excellent reproducibility, high sensitivity, and a wide range of quantification. As a consequence of this improved precision in the quantitative RT-PCR, preassay variations have greater impact on the accuracy of the viral load estimation. To compensate for these variations, we improved the assay and developed a multiplex real-time RT-PCR, which allows simultaneous calculation of the viral copy number and the individual recovery rate in an one-tube reaction. This enables the rapid and accurate calculation of copy number independent of preassay variations. In further studies, two additional real-time RT-PCR assays were designed and used to investigate the influence of sequence variations in the binding regions for either the primers or probe. Sequence mismatches in this region had a significant effect (up to 4 logarithmic decades) on reaction efficiency. In view of the inherent variability of retroviral sequences, these results underline the necessity to check reaction efficiencies before determining viral load.

Animals↗
PubMed2000

Interferon alpha-2a and 13-cis-retinoic acid in patients with metastatic renal cell cancer.

Treatment of patients with metastatic renal cell cancer (RCC) with interferon-alpha-2a (IFN) and 13-cis-retinoic acid (CRA) was first reported to be tolerable on an outpatient basis and to yield a 30% objective response rate. We sought to confirm these preliminary results by conducting a phase II trial of therapy with IFN/CRA in patients with bidimensionally measurable RCC. Twenty-five patients were enrolled. The median age was 58 (range, 47-75 years) and the median Karnofsky performance status was 90 (range 60-100). Seventeen patients (60%) had undergone prior nephrectomy and none had received prior systemic therapy. Treatment consisted of oral CRA at 1 mg/kg/day and IFN self-administered by subcutaneous injection at 3 MU/day with weekly escalation to 6 and 9 MU/day. Treatment was well tolerated, with cheilitis, influenza-like symptoms, and fatigue the most common toxicities. Severe toxicity was reversible and consisted of grade 4 cheilitis in one patient and grade 3 malaise/fatigue in two patients. One complete and four partial responses were observed, for an objective response rate of 20% (95% confidence interval, 4-36%). We conclude that treatment with CRA/IFN for RCC is tolerable on an outpatient basis and induces objective responses in some patients. The contribution, if any, of CRA to the responses observed will be determined in ongoing randomized phase III trials.

Administration, Oral↗
PubMed1998

Effect of splenectomy on slowing human immunodeficiency virus disease progression.

BACKGROUND: Lymphoreticular tissue is the most important site for human immunodeficiency virus (HIV) replication in HIV-infected individuals. OBJECTIVE: To compare the long-term effect of splenectomy on survival and time to development of acquired immunodeficiency syndrome in subjects who had undergone splenectomy with subjects who had not undergone splenectomy. DESIGN: A cohort study with a follow-up of up to 13.4 years. SETTING: Subjects were recruited from a hospital outpatient clinic population and a multicenter study of patients with hemophilia. PARTICIPANTS: Forty-five HIV-infected individuals were observed prospectively for up to 13.4 years (17 had undergone splenectomy and 28 had not undergone splenectomy). Five subjects underwent splenectomy before acquiring HIV infection and 12 underwent splenectomy during the asymptomatic phase of HIV infection. The group who did not undergo splenectomy consisted of HIV-infected individuals who were asymptomatic at study enrollment. MAIN OUTCOME MEASURES: A Cox proportional hazards model was used to test the effects of splenectomy on survival and time to development of acquired immunodeficiency syndrome when adjusting for potential confounders (age, initial CD4+ cell count, and treatment with antiretroviral drugs). Splenectomy was treated as a time-dependent covariate to account for the variation in its timing. RESULTS: During the average follow-up of 8.6 years, 9 (53%) of the 17 subjects who underwent splenectomy and 23 (82%) of the 28 subjects who did not undergo splenectomy died; acquired immunodeficiency syndrome developed in 6 (35%) of the subjects who underwent splenectomy and 23 (82%) of the subjects who did not undergo splenectomy. Splenectomy was associated with a significant reduction of risk of developing acquired immunodeficiency syndrome (adjusted relative risk [RR] <0.4, P<.05), whereas the effect on risk of mortality approached, although it did not reach, significance (adjusted RR approximately 0.5, P approximately .10). CONCLUSION: The absence of a spleen during the asymptomatic phase of HIV infection seems to have a beneficial effect on HIV disease progression.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Plasma leptin levels are increased in survivors of acute sepsis: associated loss of diurnal rhythm, in cortisol and leptin secretion.

Recent animal and human studies have suggested that leptin secretion is closely linked to the functions of the hypothalamic-pituitary-adrenal (HPA) axis and the immune system, both of which are crucial in influencing the course and outcome of critical illness. Therefore, we measured basal plasma leptin levels and examined the circadian secretion of leptin, in parallel with the hormones of the HPA axis and a key cytokine, interleukin-6, in critically ill patients with acute sepsis. Sixteen critically ill patients from the University of Leipzig Intensive Care Unit were recruited for this study. All of these patients fulfilled the standard diagnostic criteria for sepsis. Plasma leptin levels were measured in all patients and controls at 09:00. In addition, in a subgroup of eight critically ill patients and all of the nine controls plasma leptin, cortisol, ACTH and interleukin-6 concentrations were measured every 4 hours for 24 hours. Mean plasma leptin levels were three-fold higher (18.9 +/- 4.5 ng/ml) in critically ill patients than controls (3.8 +/- 1.0 ng/ml, p < 0.05). Similarly, ACTH levels were lower (7.8 +/- 3.4 pmol/l) in patients than in controls (17.1 +/- 1.5 pmol/l, p < .001), while plasma cortisol levels were increased (947.6 +/- 144 nmol/l) in patients compared to controls (361.1 +/- 29, p < 0.001). Morning plasma interleukin-6 levels were markedly elevated in all patients with sepsis (1238.0 +/- 543.1 pg/ml) versus controls (6.4 +/- 1.7, p < 0.001). The controls exhibited a nyctohemeral fluctuation in plasma leptin levels with peak levels at 23:00; in contrast, septic patients, had no nocturnal rise of leptin. In healthy controls, plasma leptin and cortisol had reciprocal circadian rhythms with high nocturnal leptin levels and low nocturnal cortisol concentrations; in critically ill patients, this relation was abolished. Mean leptin levels were three-fold higher in patients who survived the septic episode (25.5 +/- 6.2, n = 10) than in non-survivors (8.0 +/- 3.7, n = 6, p < 0.01). We conclude that in addition to its function as an anti-obesity factor, leptin may play a role in a severe stress state such as acute sepsis.

Biomarkers↗
PubMed1997

FISH probes for mouse chromosome identification.

P1 clones near the telomeres and centromeres of each mouse chromosome except Y have been selected from a mouse genomic library and mapped using fluorescence in situ hybridization (FISH). Each clone was selected to contain a genetically mapped polymorphic DNA sequence as close as possible to the centromere or telomere of a chromosome. The genetic distance from the various P1 clones to the most distal genetically mapped polymorphic sequence ranged from 0 for about half of the clones to 6.7 cM for the probe at the telomere of chromosome 14. The average distance to the most distal or proximal chromosome marker was 1.5 cM. The use of FISH with these probes for mouse chromosome identification during comparative genomic hybridization is illustrated.

Animals↗
PubMed1997

Chronic imipramine is associated with diminished hypothalamic-pituitary-adrenal axis responsivity in healthy humans.

The hypercortisolism of melancholic depression is thought to reflect hypothalamic hypersecretion of CRH and may be related to the hyperarousal associated with this syndrome. Although chronic administration of imipramine to experimental animals significantly decreases CRH messenger RNA levels in the paraventricular nucleus, it is generally thought that resolution of hypercortisolism following recovery from depression is related to the improvement in mood and decrease in anxiety that accompanies recovery rather than an intrinsic effect of imipramine. The present study was designed to explore whether chronic imipramine administration to healthy, nondepressed volunteers is associated with effects on hypothalamic-pituitary-adrenal (HPA) axis function. We studied basal and provocative measures of HPA axis function in 14 healthy volunteers before and after 6 weeks of imipramine treatment at therapeutic doses. Imipramine was associated with decreased responses in peak ACTH and cortisol to ovine CRH and in peak ACTH to arginine vasopressin (P = 0.02, P = 0.003, and P = 0.02, respectively) without changes in indices of basal HPA axis function. These data are consistent with preclinical findings and support the hypothesis that imipramine has an intrinsic effect on central components of HPA axis function, potentially related to its therapeutic effects.

Adrenocorticotropic Hormone↗
PubMed1996

Bone mineral density in women with depression.

BACKGROUND: Depression is associated with alterations in behavior and neuroendocrine systems that are risk factors for decreased bone mineral density. This study was undertaken to determine whether women with past or current major depression have demonstrable decreases in bone density. METHODS: We measured bone mineral density at the hip, spine, and radius in 24 women with past or current major depression and 24 normal women matched for age, body-mass index, menopausal status, and race, using dual-energy x-ray absorptiometry. We also evaluated cortisol and growth hormone secretion, bone metabolism, and vitamin D-receptor alleles. RESULTS: As compared with the normal women, the mean (+/-SD) bone density in the women with past or current depression was 6.5 percent lower at the spine (1.00+/-0.15 vs. 1.07+/-0.09 g per square centimeter, P=0.02), 13.6 percent lower at the femoral neck (0.76+/-0.11 vs. 0.88+/-0.11 g per square centimeter, P<0.001), 13.6 percent lower at Ward's triangle (0.70+/-0.14 vs. 0.81+/-0.13 g per square centimeter, P<0.001), and 10.8 percent lower at the trochanter (0.66+/-0.11 vs. 0.74+/-0.08 g per square centimeter, P<0.001). In addition, women with past or current depression had higher urinary cortisol excretion (71+/-29 vs. 51+/-19 micrograms per day [196+/-80 vs. 141+/-52 nmol per day], P=0.006), lower serum osteocalcin concentration (P=0.04), and lower urinary excretion of deoxypyridinoline (P=0.02). CONCLUSIONS: Past or current depression in women is associated with decreased bone mineral density.

Absorptiometry, Photon↗
PubMed1996

Naloxone-induced pituitary-adrenal activation does not differ in patients with depression, obsessive compulsive disorder, and healthy controls.

Adrenocorticotropic hormone (ACTH) and cortisol secretion have been shown to be abnormal in approximately half of depressed patients. Information from pituitary and adrenal studies suggests that the locus of this dysregulation is at or above the level of the hypothalamus; however, direct evidence from provocative studies of the hypothalamic corticotropin releasing hormone (CRH) neuron does not exist. The current study was designed to stimulate hypothalamic CRH release using the opiate antagonist naloxone in patients with depression and elevated urinary-free cortisols as well as healthy and psychiatric controls. All subjects received naloxone and placebo on separate days in a double-blinded, randomized fashion at a dose determined previously to reliably induce significant increases in ACTH and cortisol secretion. No significant differences were noted among groups. We conclude that although naloxone is an effective central stimulant of the hypothalamic CRH neuron, stimulation of the hypothalamic CRH neuron with naloxone does not provide evidence of dysregulation of the HPA axis in depression.

Adrenocorticotropic Hormone↗
PubMed1995

Opposite functions for two classes of genes of the human carcinoembryonic antigen family.

The human carcinoembryonic antigen (CEA) family can be divided into two subgroups according to the means of anchorage of member glycoproteins to the cell membrane: glycophosphatidyl inositol (GPI) linkage and transmembrane linkage. The GPI-linked members tend to be up-regulated in human tumours, whereas the transmembrane-linked members tend to be down-regulated. Thus the question as to whether the GPI members could be formally considered to function as oncogenes and the transmembrane members as tumour suppressors deserves consideration. Members of both subgroups function in vitro as intercellular adhesion molecules, but the characteristics of this adhesion, including temperature and divalent-cation dependence, differ markedly between the groups. Even the mechanism of intermolecular adhesion appears to differ fundamentally in that GPI-linked CEA-CEA binding involves a double reciprocal bonding between two domains, whereas transmembrane-linked biliary glycoprotein (BGP)-BGP binding requires only one domain. Finally, the ectopic expression of CEA in myoblasts can block myogenic differentiation leaving the cells with the ability to divide, while expression of BGP does not affect or may even accelerate myogenic differentiation. These differences in phenotypic effects in vitro thus mirror the differences observed in expression in tumours and support the view that the GPI and transmembrane groups have opposite effects on cells in relation to the malignant phenotype.

Antigens, CD↗
PubMed1993

Whey proteins as a food supplement in HIV-seropositive individuals.

On the basis of numerous animal experiments, a pilot study was undertaken to evaluate the effect of undenatured, biologically active, dietary whey protein in 3 HIV-seropositive individuals over a period of 3 months. Whey protein concentrate was prepared so that the most thermosensitive proteins, such as serum albumin which contains 6 glutamylcysteine groups, would be in undenatured form. Whey protein powder dissolved in a drink of the patient's choice was drunk cold in quantities that were increased progressively from 8.4 to 39.2 g per day. Patients took whey proteins without adverse side effects. In the 3 patients whose body weight had been stable in the preceding 2 months, weight gain increased progressively between 2 and 7 kg, with 2 of the patients reaching ideal body weight. Serum proteins, including albumin, remained unchanged and within normal range, indicating that protein replenishment per se was not likely the cause of increased body weight. The glutathione content of the blood mononuclear cells was, as expected, below normal values in all patients at the beginning of the study. Over the 3-month period, glutathione levels increased in all 3 cases. In conclusion, these preliminary data indicate that, in patients who maintain an adequate total caloric intake, the addition of "bioactive" whey protein concentrate as a significant portion of total protein intake increases body weight and shows elevation of glutathione (GSH) content of mononuclear cells toward normal levels. This pilot study will serve as a basis for a much larger clinical trial.

Body Weight↗
PubMed1992

Determination of the sequence of an expressible cDNA clone encoding ERp60/calregulin by the use of a novel nested set method.

An analysis of the N-terminal sequence of the luminal endoplasmic reticulum protein, ERp60, showed that it was identical to the well-characterized Ca2+-binding protein, calregulin. A full-length, expressible cDNA clone encoding this protein was isolated from a mouse fibroblast cDNA library. A novel nested set strategy for the production of overlapping fragments for DNA sequencing was used to determine the complete nucleotide (nt) sequence of both strands of the ERp60 clone. This method utilizes a series of nonspecific deletion primers in conjunction with a specific site primer to generate the nested set fragments. This procedure possesses several advantages over other nested set techniques, since it does not require (i) the re-cloning of the DNA insert into other vectors, (ii) any prior knowledge of the restriction sites of the nt sequence, or (iii) the transformation and analysis of bacterial subclones. ERp60 has a 17-amino acid (aa) signal sequence and the mature protein contains 399 aa with a calculated M(r) of 46,347.

Amino Acid Sequence↗
PubMed1991

Whey proteins in cancer prevention.

Epidemiological and experimental studies suggest that dietary milk products may exert an inhibitory effect on the development of several types of tumors. Some recent experiments in rodents indicate that the antitumor activity of the dairy products is in the protein fraction and more specifically in the whey protein component of milk. We and others have demonstrated that whey protein diets result in increased glutathione (GSH) concentration in a number of tissues, and that some of the beneficial effects of whey protein intake are abrogated by inhibition of GSH synthesis. Whey protein is particularly rich in substrates for GSH synthesis. We suggest that whey protein may be exerting its effect on carcinogenesis by enhancing GSH concentration.

Animals↗