Follicular growth: the basic event in the mouse and human ovary.

Follicular growth is described as a continuum. It goes on at all times, at all ages, uninterrupted by pregnancy or other periods of non-ovulation. A distinction is made between the continuum at the beginning of follicular growth and events concerning the cyclicity at the end of follicular growth, i.e. ovulation. Follicles grow sequentially. Also large follicles continue to grow until they become atretic or ovulate. No evidence for a pool of large follicles held in reserve could be found. Examination of the effect of PMSG on the growth of large follicles showed that this hormone provented the degeneration of large follicles, thus allowing more follicles to grow further. As in the mouse, follicular growth occurs during human infancy and is the normal event during childhood. Ovaries without signs of follicular growth are uncommin in the child and are apparently connected with certain systemic diseases.     

NT-pro-BNP during hypoglycemia and hypoxemia in normal subjects: impact of renin-angiotensin system activity.

Brain-derived natriuretic peptide (BNP) is a cardioprotective peptide released, together with the inactive NH(2)-terminal part of its prohormone (NT-pro-BNP), in response to different kinds of myocardial stress. Hypoglycemia and hypoxemia are conditions that threaten cellular function and hence potentially stimulate BNP release. BNP interacts with the renin-angiotensin system (RAS). The aim of this study was, therefore, to explore if basal RAS activity has an impact on NT-pro-BNP concentrations during myocardial stress induced by hypoglycemia and hypoxemia. From a cohort of 303 healthy young men, 10 subjects with high-RAS activity and 10 subjects with low-RAS activity (age 26 +/- 1 yr; mean +/- SE) were studied in a single-blinded, randomized, counterbalanced, crossover study on three occasions separated by at least 3 wk: 1) hypoglycemia (mean nadir plasma glucose 2.7 +/- 0.5 mmol/l), 2) hypoxemia (mean nadir Po(2) 5.8 +/- 0.5 kPa), and 3) normoglycemic normoxia (control). NT-pro-BNP was measured at baseline, during the stimuli, and in the recovery phase. Hypoxemia was associated with a 9% increase in NT-pro-BNP from 2.2 +/- 1.5 pmol/l at baseline to 2.4 +/- 1.5 pmol/l during hypoxemia (P < 0.001). Hypoglycemia did not affect the NT-pro-BNP level. RAS activity had no impact on NT-pro-BNP levels during hypoglycemia and hypoxemia. Hypoxemia, but not hypoglycemia, stimulates NT-pro-BNP. This indicates that cardiac defense mechanisms against hypoglycemia, if any, are probably different from those against hypoxemia. Basal RAS activity had no impact on NT-pro-BNP levels.     

Serum neopterin as a marker for reactional states in leprosy

Reactions, a relatively common phenomenon among leprosy patients in treatment, require early detection and proper management to prevent serious sequelae. It is generally accepted that reactional states are immunologically mediated and, as such, usually improve with immunomodulatory treatments such as corticosteroids or thalidomide. Neopterin, a product of gamma-interferon-activated macrophages, is a marker for cell-mediated immune activation and may be useful to detect reactional states in leprosy. Here, we compared neopterin levels in single serum samples from leprosy patients with and without reaction with untreated controls and, when available, serial samples among patients with and without reaction. Levels in the single sample measurements, conducted in 22 patients with a reversal reaction (mean 14.5 nmol l(-1), S.D. 8.7) and 13 with erythema nodosum leprosum (mean 16.9 nmol l(-1), S.D. 13.6), were significantly higher (P=0.02 and P=0.001, respectively) than levels in 26 untreated patients (mean 9.1 nmol l(-1), S.D. 7.3). Values above the upper limit of normal (10 nmol l(-1)) were found in seven of 26 untreated patients, 14 of the 22 reversal reaction patients (P=0.01) and 10 of the 13 ENL patients (P=0.003). Serial serum samples, obtained from six patients that developed reactions and 14 that remained free of reaction, indicated that reversal reaction or erythema nodosum leprosum paralleled a concomitant increase in the serum neopterin level. Neopterin levels generally declined upon corticosteroid therapy. Neopterin may be a useful marker for reactional states in leprosy by providing a laboratory parameter to assess the onset, progression, response to therapy and resolution.     

Serological study of a pleuropneumonia-like organism and an associatedCorynebacterium species

Summary The complement fixation test was employed to study the possible serological relationship between PPLO 4387 andCorynebacterium C4387. No cross reactions between the two organisms were demonstrated by the methods employed. The limitations of the complement fixation test in this study were discussed. Because of these limitations and the accumulated evidence from other types of studies, the authors concluded that the results obtained are not necessarily proof of the absence of a relationship between the PPLO and theCorynebacterium sp. This work was supported by a PHS Research Grant E-2332 from the National Institute of Allergy and Infectious Diseases, U.S. Public Health Service. This paper is part of a thesis presented to the Graduate School of the University of Maryland in partial fulfillment of the requirements for the M.S. degree in Microbiology. Mailing address: Department of Bacteriology, Walter Reed Army Institute of Research, Washington 12, D.C.     

Microbial degradation of recalcitrant compounds and synthetic aromatic polymers

The evolution of microbial catabolic enzymes cannot keep pace with the rapid introduction of novel compounds into the environment. These new synthetic compounds that are slowly biodegradable or non-biodegradable are known as recalcitrant compounds, and range from simple halogenated hydrocarbons to complex polymers. Recalcitrant compounds can be made biodegradable by developing microorganisms capable of degrading the compound and by treating the compound to make it more conducive to mirobial attack. Many factors contribute to recalcitrance. The organism may lack the necessary genetic information. The organism can acquire this information by plasmid transfer or de novo enzyme synthesis. Plasmids have been characterized that degrade or transform antibiotics, pesticides, and hydrocarbons. By the use of chemostat techniques or chemical mutagens, organisms have been shown to synthesize de novo enzymes. The compound may be too large to enter the cell, or a transport system may not exist to transport it across the membrane. The compound may be insoluble, either as a solid or a liquid, and the microorganism may lack the proper nutrients. Recalcitrant compounds can be oxygenated prior to degradation, in the presence of a readily assimilable carbon source. In the absence of the assimilable carbon source, the recalcitrant compound is not degraded, or only very slowly. Examples of such co-oxidative metabolism are alkane and lignin degradation. Polymers, particularly synthetic ones, are prime examples of difficult-to-degrade compounds. The initial rate of polymer degradation follows a Freundlich or modified Langmuir isotherm rather than Michaelis-Menten kinetics. Microorganisms can irreversibly bind to solid surfaces by various methods. Soil microorganisms have been found to degrade styrene monomers and dimers. Polystyrene has been shown to be biodegradable by ¹⁴CO₂ evolution but at a very slow rate. In car tyres, styrene as a copolymer of butadiene is co-metabolized in the presence of other assimilable carbon sources.     

Suitability of current typing procedures to identify epidemiologically linked human Giardia duodenalis isolates

BackgroundGiardia duodenalis is a leading cause of gastroenteritis worldwide. Humans are mainly infected by two different subtypes, i.e., assemblage A and B. Genotyping is hampered by allelic sequence heterozygosity (ASH) mainly in assemblage B, and by occurrence of mixed infections. Here we assessed the suitability of current genotyping protocols of G. duodenalis for epidemiological applications such as molecular tracing of transmission chains.Methodology/Principal findingsTwo G. duodenalis isolate collections, from an outpatient tropical medicine clinic and from several primary care laboratories, were characterized by assemblage-specific qPCR (TIF, CATH gene loci) and a common multi locus sequence typing (MLST; TPI, BG, GDH gene loci). Assemblage A isolates were further typed at additional loci (HCMP22547, CID1, RHP26, HCMP6372, DIS3, NEK15411).Of 175/202 (86.6%) patients the G. duodenalis assemblage could be identified: Assemblages A 25/175 (14.3%), B 115/175 (65.7%) and A+B mixed 35/175 (20.0%). By incorporating allelic sequence heterozygosity in the analysis, the three marker MLST correctly identified 6/9 (66,7%) and 4/5 (80.0%) consecutive samples from chronic assemblage B infections in the two collections, respectively, and identified a cluster of five independent patients carrying assemblage B parasites of identical MLST type. Extended MLST for assemblage A altogether identified 5/6 (83,3%) consecutive samples from chronic assemblage A infections and 15 novel genotypes. Based on the observed A+B mixed infections it is estimated that only 75% and 50% of assemblage A or B only cases represent single strain infections, respectively. We demonstrate that typing results are consistent with this prediction.Conclusions/SignificanceTyping of assemblage A and B isolates with resolution for epidemiological applications is possible but requires separate genotyping protocols. The high frequency of multiple infections and their impact on typing results are findings with immediate consequences for result interpretation in this field.     

Beta-adrenergic receptors and adenylate cyclase activity in heart, muscle and adipose tissue of German Landrace pigs selectively bred for differences in backfat deposition

The density of beta-adrenergic receptors was examined in heart, muscle (m. longissimus dorsi) and backfat tissue of German Landrace pigs using (-)-[3H]-dihydroalprenolol. The animals were selected for high (E(+)-line) or low (E(-)-line) activity of lipogenic enzymes in backfat and for low backfat thickness (U(-)-line) based on ultrasonic measurement. An unselected control (K0-line) also exists. The correlated selection response on stress susceptibility (measured by halothane reaction and by meat quality parameters) showed the following sequence of selection lines: U- greater than E- greater than E+ greater than K0. The strains used for examination descended from the 9th generation (heart and muscle tissue) and the 10th generation (heart, muscle and adipose tissue) of this selection experiment. No further selection took place between the 9th and 10th generation. Basal adenylate cyclase activity was determined as well as (-)-Isoproterenol + GTP or sodium fluoride (NaF) stimulated activity in heart and muscle of the 10th generation measuring [3H]-cAMP formation from [3H]-ATP. A good correlation (r greater than or equal to 0.59, n = 9) between beta-adrenergic receptor density and adenylate cyclase activity was found which pointed to an efficient receptor-effector system. The number of beta-adrenergic receptors and adenylate cyclase activity was higher in the U(-)-line in all investigated tissues compared to the other lines in the 9th and 10th generation. Most differences between these lines were also significant.(ABSTRACT TRUNCATED AT 250 WORDS)