Nucleotide sequence comparison of the Adh gene in three drosophilids

The alcohol dehydrogenase (Adh) gene has been isolated from Drosophila simulans and D. mauritiana by screening lambda clone libraries of each with a previously cloned Adh gene from D. melanogaster. The isolated lambda clones were subcloned and partially sequenced to determine the relatedness of these species and to examine details of evolutionary change in the structure of the Adh gene. We report the sequence of the first 704 nucleotides of each gene as well as 127 bases in the 5' untranslated region. When these sequences are compared, D. melanogaster differs from D. simulans and D. mauritiana by 2.8% and 3.1%, respectively. D. simulans and D. mauritiana differ by only 1.8%, implying that they are more closely related to each other than either is to D. melanogaster. This is consistent with phylogenetic relationships established by a variety of genetic, biochemical, and morphological means and illustrates that DNA sequencing of a single gene may be used to assess the evolutionary relationships of species.

Lorazepam in open-heart surgery--plasma concentrations before, during and after bypass following different dose regimens

Thirty-six patients (29 males and 7 females) undergoing open-heart surgery received one of three different dose regimens of lorazepam. All received a weight-related oral dose (2 mg, 3 mg or 4 mg) pre-operatively for night sedation. Twenty-four patients had an additional weight-related dose (2 mg, 3 mg or 4 mg intravenously) either as part of the induction (12 patients) or just prior to connection of the heat-lung machine (12 patients). Plasma concentrations of lorazepam were measured 20 minutes after induction, immediately before bypass, 30 and 60 on bypass and 30 minutes after bypass. Only when additional intravenous lorazepam was given prior to connection to the heart-lung machine were plasma lorazepam concentrations obtained compatible with complete amnesia.

Complement activation during cardiopulmonary bypass: quantitative study of effects of methylprednisolone and pulsatile flow

Forty four patients undergoing open heart surgery were divided into three groups. Group 1 (17 patients) underwent routine anaesthesia and surgery; group 2 (17 patients) received two doses of methylprednisolone (30 mg/kg), one during induction of anaesthesia and the other immediately before induction of cardiopulmonary bypass; and group 3 (10 patients) received pulsatile flow while undergoing pulsatile perfusion by the heart-lung machine. A modification of the previously described technique was used to detect and measure complement activation in plasma before and during the bypass period using crossed immunoelectrophoresis. About 45% of all patients showed measurable complement activation (greater than 4.5%) during cardiopulmonary bypass and the mean activation in this group was 6.4%. There was no significant difference between the three groups in complement activation. In group 2, however, women showed significantly more complement activation than men (p less than 0.05). It is suggested that neither corticosteroids nor pulsatile flow affect complement activation, but caution should be exercised in women receiving methylprednisolone.

Catecholamine synthesis inhibitors acutely modulate [3H]estradiol binding by specific brain areas and pituitary in ovariectomized rats

Drugs known to alter endogenous levels of catecholamines were administered to adult ovariectomized rats to assess catecholaminergic effects on estradiol (E2) uptake and binding in nuclear and supernatant fractions of pituitary and specific brain regions and on cytoplasmic E2 receptor numbers and affinities. Specific (i.e. diethylstilbestrol-blockable) binding in vivo was measured 1 h after the iv injection of [3H]E2 (1 micrograms/kg). Administration of the tyrosine hydroxylase inhibitor alpha-methyl-p-tyrosine (alpha MPT) 2 h before [3H]E2, to reduce levels of dopamine (DA), norepinephrine (NE), and epinephrine (Ep), decreased total and specific [3H]E2 binding by 36-56% in the nuclear fraction of the anterior pituitary, basal hypothalamus, and anterior hypothalamus. The dopamine-beta-hydroxylase inhibitor diethyldithiocarbamate (DDC), administered 2 h before [3H]E2 to reduce levels of only NE and Ep, increased the total and specific uptake of [3H]E2 by 62-140% in nuclear and supernatant fractions of the anterior pituitary and also increased uptake in several brain areas. In vitro analysis of hypothalamic and pituitary cytoplasms showed that in vivo administration of DDC increased E2 binding. Scatchard analysis showed that DDC increased receptor numbers 18-29%, with no change in the dissociation constant in pituitary cytoplasms. At the same time, plasma PRL levels were reduced by DDC treatment, indicating that DDC had increased DA output. Phenoxybenzamine (a blocking agent at alpha 1 postsynaptic binding sites) and a high dose of clonidine (a pre- and postsynaptic alpha-receptor agonist) did not significantly alter specific uptake in the cell nuclear fraction of any tissue, suggesting that postsynaptic alpha-receptors do not play a major role in modulating [3H]E2 uptake. No drug altered plasma levels of radioactivity. Because alpha-methyl-p-tyrosine and DDC both inhibit synthesis of NE and Ep, it is suggested that their opposite effects on uptake of [3H]E2 are related to their opposite effects on DA output. This interpretation is compatible with our previous observations that DA agonists increase [3H]E2 uptake in brain and pituitary in ovariectomized rats.

Restricted adult clonal profiles induced by neonatal immunization. Influence of suppressor T cells

The effects of neonatal antigen exposure on the adult B cell repertoire have been examined by characterizing the influenza hemagglutinin (HA)-specific response of adult BALB/c mice given antigen soon after birth. Ligand exposure during early life exerts a profound and lasting effect upon the B cell repertoire, characterized by the expansion and preservation of particular antigen-reactive clones and the apparent loss of others. The precise subset of clonotypes selectively preserved depends upon the age at which antigen is first encountered; and is predictable given a knowledge of the emerging primary pool's dynamics and composition. The preserved (secondary) B cells differ from their unprimed precursors with respect to (a) expression of the surface marker detected by the monoclonal antibody J11d, and (b) susceptibility to T cell-mediated suppression. These studies thus demonstrate a strong relationship between the heritable dynamics of the emerging primary B cell repertoire and the effect of ligand-driven events upon repertoire phenotype. In addition, they provide a mechanistic model for certain forms of antigen-induced oligoclonal dominance, especially the phenomenon of original antigenic sin.

Adenovirus type 7b in a children's hospital

Between August 15 and September 15, 1980, an outbreak of infections due to adenovirus type 7b occurred at Children's Hospital and Health Center, San Diego, California. During that time, four of six patients infected with adenovirus type 7b died. All patients with hospital-acquired disease had underlying respiratory compromise. Cultures, adenoviral serology tests, and histories were obtained from 383 (93%) of the 410 hospital employees. All 11 people from whom adenovirus type 7 was cultured were nurses working in a unit with an infected patient. Seven other employees with negative cultures had a fourfold or greater rise in their adenoviral complement fixation titers. This outbreak demonstrates that adenovirus type 7 infections are capable of causing serious and potentially fatal disease in hospitalized patients and suggests that individuals with underlying respiratory diseases are especially at risk.

Dynamics of B cell repertoire formation: normal patterns of clonal turnover are altered by ligand interaction

The dynamics of B cell repertoire formation was examined by defining the kinetics and clonal composition of the influenza hemagglutinin- (HA) responsive BALB/c repertoire at 1 and 2 wk of age. Although the size and diversity of the HA-responsive repertoire remain constant during this period, the clonal composition changes significantly. These findings indicate a rapid and regular turnover of clonal specificities within the emerging primary repertoire. In addition, the effect of ligand exposure on this process was analyzed by characterizing the repertoire of 2-wk-old BALB/c mice that had been immunized with virus during their first week of life. This treatment markedly alters the normal kinetics and turnover of the emerging repertoire. First, many clonotypes that normally arise between 1 and 2 wk of age fail to be expressed in detectable numbers. Second, several clonotypes that are normally only transiently expressed at 1 wk of age are preferentially expanded and preserved within the responsive B cell pool. In conjunction, these results demonstrate that a) the primary repertoire is characterized by rapid and regular turnover in clonotype composition, b) antigenic exposure perturbs the normal kinetics and pattern of this turnover, and c) the exact effects of ligand exposure may depend on the developmental stage at which it occurs.

Dynamics of B cell repertoire formation: normal patterns of clonal turnover are altered by ligand interaction

The dynamics of B cell repertoire formation was examined by defining the kinetics and clonal composition of the influenza hemagglutinin- (HA) responsive BALB/c repertoire at 1 and 2 wk of age. Although the size and diversity of the HA-responsive repertoire remain constant during this period, the clonal composition changes significantly. These findings indicate a rapid and regular turnover of clonal specificities within the emerging primary repertoire. In addition, the effect of ligand exposure on this process was analyzed by characterizing the repertoire of 2-wk-old BALB/c mice that had been immunized with virus during their first week of life. This treatment markedly alters the normal kinetics and turnover of the emerging repertoire. First, many clonotypes that normally arise between 1 and 2 wk of age fail to be expressed in detectable numbers. Second, several clonotypes that are normally only transiently expressed at 1 wk of age are preferentially expanded and preserved within the responsive B cell pool. In conjunction, these results demonstrate that a) the primary repertoire is characterized by rapid and regular turnover in clonotype composition, b) antigenic exposure perturbs the normal kinetics and pattern of this turnover, and c) the exact effects of ligand exposure may depend on the developmental stage at which it occurs.

Plasma levels of methylprednisolone following administration during cardiac surgery

Methylprednisolone was given to patients undergoing open-heart surgery in a dose of 30 mg/kg administered following induction of anaesthesia and repeated with the start of cardiopulmonary bypass. The effects of this treatment on 2,3-DPG. P50 and cardiac index were compared with a control group who did not receive steroids. In addition plasma levels of methylprednisolone were assayed throughout the operations and up to 24 hours postoperatively. There was no significant difference between the two groups despite apparently adequate plasma levels of methylprednisolone, and it is concluded that steroids do not affect the P50 or 2,3-DPG in patients undergoing cardiopulmonary bypass.

Senior registrar rotations. A survey of rotational arrangements

A questionnaire was circulated to assess the extent and nature of problems with senior registrar rotations. Proper notice of an impending move, suitable accommodation provided at the rotation hospital, and a clear indication of which hospitals are involved in the rotation should reduce the number of difficulties encountered.

Methylprednisolone prior to cardiopulmonary bypass

Patients undergoing cardiopulmonary bypass were randomly allocated to receive methylprednisolone 30 mg/kg in a single dose prior to bypass, or to a control group receiving saline. The effect of this treatment on 2,3-DPG and oxygen delivery to the tissues was determined. There was no difference between the groups in 2,3-DPG levels, P50 or oxygen availability, but the methylprednisolone group showed a highly significant difference in oxygen consumption immediately following cardiopulmonary bypass (p < 0.001) and a significant difference in serum phosphate levels in the immediate postoperative period (p < 0.05). Methylprednisolone levels were measured by radioimmunoassay, and these showed a rapid decline in the 4 hours following administration.

Arterial pressure and pulse interval responses to repetitive carotid baroreceptor stimuli in man

1. Carotid baroreceptors of eight healthy young men were stimulated with brief (0.6 sec), moderate (30 mmHg), single or repetitive (2, 3 or 5), R wave coupled neck suction during held expiration, and brachial arterial pressure and pulse interval changes were measured for 10 sec. 2. Mean systolic arterial pressure declined significantly from control levels after single or multiple baroreceptor stimuli. The reduction of systolic pressure was significant within the first sec after the onset of trains of baroreceptor stimuli; its duration was proportional to the number of stimuli. 3. The sinus node response to a single baroreceptor stimulus was biphasic: inhibition was followed by less intense, but more prolonged facilitation (cardio-acceleration). A single baroreflex stimulus modulated sinus node function for about 7 sec. The integral of sinus node inhibition was linearly related to the number of baroreceptor stimuli. Inhibition with five repetitive stimuli peaked at about 1.5 sec after the onset of stimulation and delcined to a new steady-state level during the period of baroreceptor stimulation. 4. Human baroreflex adjustments of arterial pressure and sinus node function occur very early after a step increase of phasic baroreceptor afferent activity. The perturbation of sinus node function is complex and probably reflects changing temporal relationships between the arterial pulse and sinus node activity, and interactions between oscillating levels of acetylcholine and sinus node responsiveness to acetylcholine.

False-positive reactions in the rapid plasma reagin-card, fluorescent treponemal antibody-absorbed, and hemagglutination treponemal syphilis serology tests

Sera from 628 nonsyphilitic individuals were tested with the Rapid Plasma Reagin-Card, Fluorescent Treponemal Antibody-Absorbed, and Hemagglutination Treponemal Test for Syphilis tests to ascertain the comparative specificity of these tests. Many sera were also tested with the quantitative Venereal Disease Research Laboratory test. Sera included in the study were from both normal individuals and patients with a variety of illnesses and conditions. The Hemagglutination Treponemal Test for Syphilis gave the lowest overall percentage of false-positive reactions (1.6%), followed by the Fluorescent Treponemal Antibody-Absorbed test (3.3%) and the Rapid Plasma Reagin-Card test (10.8%).