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Biomedical subjects

B Greenberg

Publications and source records attributed to B Greenberg.

At least 73 records · Page 4Linked to original sources
PubMed1995

Species identification of calliphorid (Diptera) eggs.

Eggs of 11 forensically important calliphorid species belonging to six genera were studied with SEM for useful diagnostic characters. Identification was confounded by the following three factors: (1) variability within and among populations of the same species, (2) similarities among some congeneric species, and (3) similarities between some species of different genera. Reliable separation based on morphology should take into account relevant aspects of blow fly biology as it is affected by locality, climate, season, and weather.

Animals↗
PubMed1995

A cluster of four genes encoding enzymes for five steps in the folate biosynthetic pathway of Streptococcus pneumoniae.

Two genes, sulB and sulC, in a folate biosynthetic gene cluster of Streptococcus pneumoniae were identified after determination of the DNA sequence between two previously reported genes, sulA and sulD, in a cloned segment of chromosomal DNA containing a mutation to sulfonamide resistance. The gene products, SulB and SulC, correspond to polypeptides of 49 and 21 kDa, respectively. SulC has GTP cyclohydrolase activity and catalyzes the first step in the folate biosynthetic pathway. SulB apparently has dihydrofolate synthetase activity in that it complements a folC mutant of Escherichia coli and thus catalyzes the last step in the pathway. Prior work showed that SulA, a dihydropteroate synthase, and SulD, a bifunctional enzyme, catalyze three intervening steps. Mapping of the mRNA transcribed from the operon was consistent with its beginning at a promoter with a -35 site (gTGtCc) and an extended -10 site (T-TG-TAaAAT) and its termination at the end of a hairpin structure, which would give a transcript 3,745 nucleotides in length. SulC showed a considerable conservation of sequence by comparison with proven or putative GTP cyclohydrolases from four unrelated species, with 38 to 53% of the residues being identical. A similar comparison of SulB with dihydrofolate synthetases showed an identity of only 26 to 37%. Overall, comparisons of the five folate biosynthetic enzymes in different species suggest that S. pneumoniae is related more closely to other gram-positive bacteria, less closely to eucaryotes, and least closely to the gram-negative E. coli. The varied arrangements of folate biosynthetic genes in different species imply an early evolutionary period of fluidity in genomic rearrangement.

Amino Acid Sequence↗
PubMed1995

Beta-Amyloid peptide and amyloid precursor proteins in olfactory mucosa of patients with Alzheimer's disease, Parkinson's disease, and Down syndrome.

Dystrophic neurites are present in olfactory epithelium (OE) of patients with Alzheimer's disease (AD), Parkinson's disease (PD), and Down syndrome (DS) and occasionally in normal individuals. Cultured olfactory neuroblasts from AD patients generate carboxy terminal amyloid precursor protein (APP) fragments that contain beta-amyloid (A beta), but it is not known if deposits of A beta and/or APP fragments occur in the OE of individuals with or without AD, PD, or DS. To determine if A beta accumulates in the OE in situ, we probed postmortem samples of olfactory mucosa from patients with AD, PD, and AD (PD/AD), and DS and AD (DS/AD), as well as from controls, using polyclonal and monoclonal antibodies to A beta and flanking sequences in APPs. Samples of OE also were examined by thioflavin-S and electron microscopy. Labeling of A beta was observed in 10 of 12 AD cases, 2 of 3 PD/AD cases, 3 of 4 DS/AD cases, 3 of 10 adult controls, and 4 of 6 fetal cases. The A beta staining was seen in the basal third of the OE, in axons projecting through the lamina propria, and in metaplastic respiratory epithelium within the OE. Antibodies to other APP domains stained the OE of patients and controls. Thioflavin-S staining was present in the basal third of the OE of 8 of 9 AD patients and several PD/AD and DS/AD patients, but only in rare cells of 3 controls. Electron microscopy did not reveal amyloid fibrils in the OE.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Oral ondansetron for the control of cisplatin-induced delayed emesis: a large, multicenter, double-blind, randomized comparative trial of ondansetron versus placebo.

PURPOSE: To investigate the efficacy and safety of oral ondansetron in the control of cisplatin-induced delayed emesis in patients who do not require rescue antiemetic therapy for acute emesis. PATIENTS AND METHODS: Five hundred thirty-eight chemotherapy-naive patients who received cisplatin chemotherapy (> or = 70 mg/m2), and who were not rescued for acute emesis, were eligible to be randomized to receive one of the three oral regimens to control delayed emesis. Group I received placebo on days 2 to 6; group II received ondansetron 8 mg twice daily on days 2 and 3 and placebo on days 4 to 6; group III received ondansetron 8 mg twice daily on days 2 to 6. All patients received intravenous ondansetron (0.15 mg/kg every 4 hours for three doses) for the control of acute emesis on day 1. The number of emetic episodes on days 2 and 3 combined (days 2/3, when incidence and severity of delayed emesis were expected to be greatest) was considered the primary measure of efficacy. RESULTS: Patients who received odansetron had significantly fewer emetic episodes on days 2/3, 4, and 5 than those who received placebo (P < or = .002 on each day). Additionally, significantly more patients who received ondansetron had a complete plus major response (C+MR; < or = two two emetic episodes) than those who received placebo on days 2/3 (56% v 37%, P = .001), 4 (94% v 85%, P = .005), and 5 (98% v 88%, P = .006). Patients who received ondansetron had significantly less nausea on day 2/3 when day-1 nausea was used as the baseline score (P = .025). Patients who received ondansetron also had significantly less nausea on day 4 (P = .042) and the results approached significance on day 5 (P = .066). CONCLUSION: Oral ondansetron had a significant effect in the control of cisplatin-induced delayed emesis and nausea in patients who had not required rescue antiemetics during the acute emesis period. The control of delayed nausea and vomiting was most notable in the immediate 2 days following cisplatin administration, with the clinical difference narrowing between the two treatment arms on subsequent days.

Administration, Oral↗
PubMed1995

Bronchogenic carcinoma presenting as a pseudopregnancy.

A young woman with an occult bronchogenic carcinoma presented with secondary amenorrhea and an elevated beta subunit of human chorionic gonadotropin that was mistakenly attributed to pregnancy. Physicians should be aware that this carcinoma may present solely with an elevated beta human chorionic gonadotropin value, and the potential exists for confusion with a pregnancy state in women of childbearing age.

Adult↗
PubMed1995

Polymorphisms of the beta fibrinogen gene and plasma fibrinogen concentration in Caucasian and Japanese population samples.

We reported previously that plasma fibrinogen was significantly higher in U.S. Caucasians than in Japanese, which may contribute to the higher mortality rate of coronary heart disease in the United States than in Japan. To examine the contribution of genetic variations to the race difference in plasma fibrinogen levels, restriction fragment length polymorphisms (RFLPs) of the beta fibrinogen gene were examined in 293 nonsmoking Caucasians and Japanese men and women aged 47-69 years. Three RFLPs were detected by digestion of genomic DNA using the BclI restriction enzyme, polymerase chain reaction (PCR) products using HaeIII and HindIII. The alleles B2 (4.2 kb, BclI digestion), H2 (957 b, HaeIII) and Hd2 (465 b. HindIII) were associated with higher fibrinogen concentrations in previous studies. Because of a strong linkage disequilibrium between HaeIII and HindIII polymorphisms, the data of HindIII was presented. The frequency of the B2 allele was 22% (95% Cl: 17-27%) for Caucasians and 13% (10-17%) for Japanese (the difference: p < 0.01). The respective frequency of the Hd2 allele was 26% (21-31%) and 12% (8-16%) (p < 0.001). After controlling for age, body mass index, alcohol intake, triglycerides, fish intake, and for women, menopausal status and hormone replacement therapy, the adjusted mean fibrinogen level among Caucasians was 289 mg/dl for genotype B1B1 and 301 mg/dl for genotype B1B2 or B2B2 combined (p = 0.18), and 285 mg/dl for Hd1Hd1 and 306 mg/dl for Hd1Hd2 or Hd2Hd2 combined (p = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Relation of neurohumoral activation to clinical variables and degree of ventricular dysfunction: a report from the Registry of Studies of Left Ventricular Dysfunction. SOLVD Investigators.

OBJECTIVES: This study examined the relation between neurohumoral activation and severity of left ventricular dysfunction and congestive heart failure in a broad group of patients with depressed left ventricular function who were not recruited on the basis of eligibility for a therapeutic trial. BACKGROUND: Previous studies have established the presence of neurohumoral activation in patients with severe congestive heart failure. It is not known whether the activation of these neurohumoral mechanisms is related to an impairment in left ventricular function. METHODS: From the 6,273 patients recruited into the Studies of Left Ventricular Dysfunction Registry (SOLVD), a subgroup of 859 patients were randomly selected, and their plasma norepinephrine, plasma renin activity, arginine vasopressin and atrial natriuretic peptide levels were correlated with clinical findings, New York Heart Association functional class, left ventricular ejection fraction and drug use. RESULTS: There was a weak but significant correlation between ejection fraction and an increase in plasma norepinephrine (rho = -0.18, p < 0.0001), plasma renin activity (rho = -0.24, p < 0.0001) and arginine vasopressin (rho = -0.12, p < 0.003). The only exception was atrial natriuretic peptide, which showed the best correlation to ejection fraction (rho = -0.37, p < 0.0001). Deterioration in functional class was associated more with increases in atrial natriuretic peptide (p = 0.0003) and plasma renin activity (p = 0.0003) and less with an increase in plasma norepinephrine. Of the clinical variables, elevated jugular venous pressure and third heart sound (S3) gallop were significantly associated with increased levels of plasma norepinephrine, plasma renin activity and atrial natriuretic peptide. We then compared the relation of neurohormones with clinical signs, functional status, ejection fraction and drug therapy and controlled for mutual interactive effects. After adjustment, a decrease in ejection fraction was still significantly related to an increase in plasma norepinephrine, plasma renin activity and atrial natriuretic peptide. In contrast, only a difference between functional classes I and III/IV was associated with an increase in plasma renin activity and atrial natriuretic peptide levels. CONCLUSIONS: Neurohumoral activation in patients with heart failure is related to severity of left ventricular functional depression, and this relation is independent of functional class or concomitant drug therapy.

Aged↗
PubMed1994

Fatal disseminated intravascular coagulation and pulmonary thrombosis following blood transfusion in a patient with severe autoimmune hemolytic anemia and human immunodeficiency virus infection.

BACKGROUND: Autoimmune hemolytic anemia (AIHA) has rarely been reported in association with human immunodeficiency (HIV) infection and never as a presenting manifestation. Similarly, disseminated intravascular coagulation (DIC) is a very infrequent complication of HIV infection. CASE REPORT: An unusual patient is described who at the time of presentation with severe AIHA was found to be HIV positive. Shortly thereafter, he developed DIC, pulmonary thrombi, and right heart failure that proved fatal, in spite of intensive supportive measures. CONCLUSION: Although the etiology of the DIC and pulmonary thrombi could not be established, they are most likely related to aggressive transfusion therapy, with associated intravascular hemolysis.

Adult↗
PubMed1994

Effect of the red imported fire ant (Hymenoptera: Formicidae) and carcass type on the daily occurrence of postfeeding carrion-fly larvae (Diptera: Calliphoridae, Sarcophagidae).

Red imported fire ants, Solenopsis invicta Buren, caused an increased in the proportion of gaps in the daily occurrence of postfeeding larvae of Cochliomyia macellaria (F.) in carrion-baited traps. Chrysomya rufifacies appeared later in the decomposition process and over a wider period of days in goat than in rabbit carcasses. The dependence of presence or absence of a carrion arthropod taxon at a given point in succession on interactions between other arthropods or carcass type must be considered when using successional data to estimate postmortem intervals.

Animals↗
PubMed1994

Survival after submergence in the pupae of five species of blow flies (Diptera: Calliphoridae).

Survival of pupae of known ages after 1 to 5 d of submersion under water was assessed by determining the emergence of Protophormia terraenovae (Robineau-Desvoidy), Calliphora vicina (Robineau-Desvoidy), Cochliomyia macellaria (F.), Phormia regina (Meigen), and Phaenicia sericata (Meigen). Survival after 1 d of submergence was < 14% in the white puparial stage, 0-100% in pharate adults nearing eclosion, and approximately 100% in pupae between these two stages. This pattern inversely tracks O2 consumption during metamorphosis. Twenty-five percent of the pupae of three species (P. terraenovae, P. regina, and P. sericata) produced normal adults after 4 d of submersion, but none after 5 d. Among survivors, the pupation period was extended by the duration of submersion. Pupae of C. vicina were least able to withstand drowning. These data are potentially useful in estimating duration of submergence of a corpse in forensic investigations where the corpse becomes submerged after the larvae have developed and pupariated.

Animals↗
PubMed1994

An unusual late relapse in pathologic stage I non-seminomatous germ cell tumor: case report and review of the literature.

Late relapses are exceedingly uncommon in patients with pathologic stage (PS) I non-seminomatous germ cell tumors (NSGCT) of the testis treated with inguinal orchiectomy and retroperitoneal lymph node dissection (RPLND). We describe an unusual patient with PSI NSGCT who relapsed 40 months after surgery. The only evidence of recurrent disease was an elevated serum alpha-fetoprotein level, and complete remission was achieved following the prompt institution of combination chemotherapy. To our knowledge, this is the first report of a late relapse in PSI NSGCT of the testis manifested only as an elevated tumor marker.

Adult↗
PubMed1994

Tissular expression and regulation of type 1 angiotensin II receptor subtypes by quantitative reverse transcriptase-polymerase chain reaction analysis.

Recent studies have revealed that angiotensin II (Ang II) interacts with two pharmacologically different types of seven-transmembrane domain receptors, hence named Ang II type 1 and type 2 (AT1 and AT2) receptors. cDNAs for the AT1 receptor have been cloned, and the existence of two receptor subtypes, AT1A and AT1B, has been revealed in rat and mouse. This study presents a new approach for the specific quantification of AT1A and AT1B receptor mRNAs by reverse transcription and polymerase chain reaction amplification in the presence of an AT1 receptor mutant cRNA as internal standard. Absolute quantities of mRNA are then determined by extrapolation using the standard curve generated with the internal standard. Moreover, addition of this internal standard to each tube controls for both reverse transcription and polymerase chain reaction amplification in each sample. In male Wistar rats, the highest absolute AT1A receptor mRNA levels were found in liver and kidney and those for AT1B receptor mRNA in the pituitary. Expressed as a percentage of total AT1A+AT1B receptor mRNA content, AT1A receptor mRNA content was 100% in liver, 85% in lung, 73% in kidney, 65% in aorta, 48% in adrenals, and 15% in the hypophysis. Since this approach can determine absolute AT1A and AT1B receptor mRNA quantities in different organs, it allows the study of the regulation of their expression under different pathophysiological conditions. After sodium depletion, known to induce hyperactivity of the renin-angiotensin system, adrenal AT1A and AT1B receptor mRNA levels were increased by 60% and 110%, respectively. In contrast, in renovascular hypertension (two-kidney, one clip), also associated with elevated circulating plasma renin activity, adrenal AT1B receptor mRNA levels decreased by 50%, whereas there was no change in those of AT1A. Therefore, the differential distribution and regulation of these two receptor subtypes suggest that each of them might be involved in the mediation of different biological effects of Ang II.

Adrenal Glands↗
PubMed1994

Role of vasodilator therapy in congestive heart failure. Effects on mortality.

Congestive heart failure is associated with a considerable reduction in survival with only about 50% of patients alive within 5 years of its diagnosis. Recent trials have demonstrated that vasodilator therapy can improve survival in this condition. Agents that have been shown to be effective in well-designed double-blind clinical trials include the combination of hydralazine-isosorbide dinitrate (in V-HeFT) and the angiotensin converting enzyme inhibitors (in SOLVD, SAVE, and CONSENSUS).

Clinical Trials as Topic↗
PubMed1993

Binding of vascular heparan sulfate proteoglycan to Alzheimer's amyloid precursor protein is mediated in part by the N-terminal region of A4 peptide.

The exact mechanisms of deposition and accumulation of amyloid in senile plaques and in blood vessels in Alzheimer's disease remain unknown. Heparan sulfate proteoglycans may play an important role in amyloid deposition in Alzheimer's disease. Previous investigations have demonstrated high affinity binding between heparan sulfate proteoglycans and the amyloid precursor, as well as with the A4 peptide. In the current studies, a specific vascular heparan sulfate proteoglycan found in senile plaques bound with high affinity to two amyloid protein precursors (APP695 and APP770). Vascular heparan sulfate proteoglycan also bound the Alzheimer's amyloid A4 peptide, and not other amyloid protein precursor regions studied, with high affinity. Both heparan sulfate glycosaminoglycan chains and chemically deglycosylated vascular heparan sulfate proteoglycan protein core bound to A4. High affinity interactions between vascular heparan sulfate proteoglycan and the A4 peptide may play a role in the process of amyloidogenesis in Alzheimer's disease, by localizing the site of deposition of A4, protecting A4 from further proteolysis, or by promoting aggregation and fibril formation.

Alzheimer Disease↗
PubMed1993

Altered epidermal growth factor signal transduction in activated Ha-ras-transformed human keratinocytes.

Epidermal growth factor (EGF) can stimulate proliferation and 92 kDa gelatinase/matrix metalloproteinase (MMP-9) expression. The induction of MMP-9 is not only pathologically significant for invasion and metastasis, but also serves as a semiquantitative measure of EGF signal transduction. In order to examine the role of mutated ras p21 in EGF signal transduction, an activated Ha-ras-transformed human keratinocyte cell line was developed and characterized. Overexpression of the mutated Ha-ras p21 in these cells was demonstrated. Our results showed that EGF induced 92 kDa MMP-9 secretion was doubled in the ras-transformed keratinocytes in comparison to the parent cells. The karyotype, the expression of EGF receptor (EGFR) and transforming growth factor (TGF) alpha at the mRNA level remained unchanged. These results suggest that the presence of high levels of mutated ras p21 may be responsible for the aberrant EGF signal transduction and contributes to transformation. In addition, a reduction of TGF beta expression at mRNA level by 70% was found in the activated Ha-ras-transformed keratinocytes when compared to the parent cells.

Cell Line, Transformed↗
PubMed1993

Comparative neurohormonal responses in patients with preserved and impaired left ventricular ejection fraction: results of the Studies of Left Ventricular Dysfunction (SOLVD) Registry. The SOLVD Investigators.

OBJECTIVES: The aim of this study was to determine the differences in neurohumoral responses between patients with pulmonary congestion with and without impaired left ventricular ejection fraction. BACKGROUND: Previous studies have established the presence of neurohumoral activation in patients with congestive heart failure. It is not known whether the activation of these neurohumoral mechanisms is related to the impairment in systolic contractility. METHODS: The 898 patients recruited into the Studies of Left Ventricular Dysfunction (SOLVD) Registry substudy were examined to identify those patients with pulmonary congestion on chest X-ray film who had either impaired (< or = 45%, group I) or preserved (> 45%, group II) left ventricular ejection fraction. Plasma norepinephrine, plasma renin activity, arginine vasopressin and atrial natriuretic peptide levels were measured in these two groups of patients and compared with values in matched control subjects. RESULTS: Distribution of the New York Heart Association symptom classification was the same in the two groups of patients. Compared with control subjects, patients in group II with pulmonary congestion and preserved ejection fraction had no activation of the neurohumoral mechanisms, except for a small but statistically significant increase in arginine vasopressin and plasma renin activity. Compared with patients in group II, those in group I with pulmonary congestion and impaired ejection fraction had significant increases in plasma norepinephrine (p < 0.002), plasma renin activity (p < 0.02) and atrial natriuretic peptide levels (p < 0.0007). When we controlled for baseline differences between groups I and II, the between-group differences in plasma norepinephrine (p < 0.02) and atrial natriuretic peptide (p < 0.002) remained significant. However, plasma renin activity was not significantly different between groups I and II. When the effects of diuretic agents and angiotensin-converting enzyme inhibitors were adjusted, patients with lower ejection fraction were found to have significantly higher plasma norepinephrine and atrial natriuretic peptide levels. CONCLUSIONS: The results point to the importance of the decrease in left ventricular ejection fraction as one of the mechanisms for activation of neurohormones in patients with heart failure.

Adult↗
PubMed1993

Different developmental strategies in two boreal blow flies (Diptera: Calliphoridae).

The minimum developmental rates of Protophormia terraenovae (Robineau-Desvoidy) and Calliphora vomitoria (L.) were measured at four temperatures: 12.5, 23, 29, and 35 degrees C. Although both species are Holarctic in distribution and hemisynanthropic, there are important differences in the response of their developmental stages to various temperature regimes. The eggs and feeding larvae of P. terraenovae responded linearly to temperatures from 23 to 35 degrees C, but development was retarded at 12.5 degrees C. The feeding larvae took about 11 times longer to develop at 12.5 than at 23 degrees C, indicating poor cold adaptation. The converse is true of C. vomitoria, which took only 2 times as long at 12.5 than at 23 degrees C but failed to complete development at 29 and 35 degrees C. Our laboratory data and field studies of others suggest that, in nature, P. terraenovae and C. vomitoria prefer breeding in larger carcasses as a survival tactic and means of extending their distribution into colder regions.

Acclimatization↗