PRENATAL CARE—A Group Psychotherapeutic Approach

It has been well established that “normal” pregnancy gives rise to much anxiety whose source is variable. When not adequately dealt with, the anxiety may masquerade in the guise of physical symptoms such as fatigue, dizziness, nausea and vomiting, or, more often, as disquieting emotional counterparts, like irritability and depression.A study was undertaken in the outpatient obstetrical department at U.C.L.A. utilizing a group psychotherapeutic approach. The results helped the patients and offered training to staff in dealing with emotional problems of pregnancy. Patients were seen in groups of seven, twice a month for one-hour sessions. Participating in each group were an obstetrical resident, a psychiatric resident and a nurse. The subject material was not selected beforehand. Groups were similar in that the expected time of delivery of the patients was approximately the same. Results of the study suggested that the much needed emotional support may be supplied in this way with little to no additional time expenditure on the part of the physician or nurse.     

Kinetic relations of the Na-amino acid interaction at the mucosal border of intestine

The relation between unidirectional influxes of Na and amino acids across the mucosal border of rabbit ileum was studied under a variety of conditions. At constant Na concentration in the mucosal bathing solution, amino acid influx followed Michaelis-Menten kinetics permitting determination of maximal influx and the apparent Michaelis constant, K_t. Reduction in Na concentration, using choline as substitute cation, caused an increase in K_t for alanine but had no effect on maximal alanine influx. The reciprocal of K_t was a linear function of Na concentration. Similar results were obtained for valine and leucine and these amino acids competitively inhibited alanine influx both in the presence and in the absence of Na. These results lead to a model for the transport system which involves combination of Na and amino acid with a single carrier or site leading to penetration of both solutes. The model predicts that alanine should cause an increase in Na influx and the ratio of this extra Na flux to alanine flux should vary with Na concentration. The observed relation agreed closely with predicted values for Na concentrations from 5 to 140 mM. These results support the hypothesis that interactions between Na and amino acid transport depend in part on a common entry mechanism at the mucosal border of the intestine.     

Apparatus for monitoring the oxygen uptake and carbon dioxide production of fermentations

The requirements of the continuous analysis of effluent gas streams from aerated flash and tank fermentors are described, as are instrumental devices for measuring the oxygen and carbon dioxide content of fermentor gases. The use of a specially designed sequential gas sample for monitoring four fermentations simultaneously and a system for precise control of low air flow and pressure is explained. Equations for calculating carbon dioxide production or oxygen consumption rates and respiratory quotients are given. A discussion of the operating characteristics of a device for automatic translation of aeration data between fermentors is presented.     

Hindlimb suspension suppresses muscle growth and satellite cell proliferation

The effects of long-term hindlimb unweighting by tail suspension on postnatal growth of 20-day rat extensor digitorum longus (EDL) and soleus muscles were studied. Morphological assay indicated that radial growth of soleus myofibers was completely inhibited between 3 and 10 days of suspension and reduced thereafter, leading to a severe attenuation (-76% from control) over the total experimental period. Longitudinal growth rate, however, was accelerated 40% over weight-bearing controls. In addition, myofibers were arranged parallel to the long axis of the muscle, an orientation associated with chronologically younger muscles, suggesting morphological maturation of the soleus muscle had been delayed by suspension. In contrast, radial and longitudinal growth of EDL myofibers were minimally affected under similar conditions and remained within approximately 5% of control at all times. Suspension also influenced the normal changes that occur in satellite cell and myonuclear populations during postnatal growth. Both the number and proliferative activity of satellite cells were severely reduced in individual myofibers after only 3 days in both soleus and EDL muscles. The reduced number of satellite cells within 3 days of initiating hindlimb suspension appeared to be the result of their incorporation into myofibers while the long-lasting reduction appeared to be the added effects of decreased proliferative activity. In the soleus, this reduction in number and proliferation of satellite cells persisted throughout the experimental period and resulted in an overall 43% fewer myonuclei and 45% fewer satellite cells than control at 50 days of age. In contrast, both the total number and mitotic activity of satellite cells in the EDL rapidly returned to weight-bearing control levels by day 10 of suspension, resulting in no overall reduction in myonuclear accretion.     

A simple Hill element-nonlinear spring model of muscle contraction biomechanics

The purpose of this study was to develop a model to predict the mechanical response of muscles during isometric tetanic, afterloaded isotonic and isovelocity shortening contractions. Two versions of the model were developed. Both incorporated a contractile element that obeyed a Hill force-velocity relationship and a series elastic element. In a quadratic spring version, the series elastic element force was represented as proportional to the square of the stretch; in a cubic spring version, it was represented as proportional to the cube of the stretch. Both versions provided closed-form equations for response predictions that involved four independent parameters. Once the four parameters were chosen, each of these responses could be predicted. Model validity was established by comparing predicted and observed responses in slow and fast hindlimb muscles of rodents. Significant model-predicted responses seldom differed by more than 15% from experimental values. The model can provide insights into how changes in individual properties affect the overall mechanical behavior of muscles in a variety of circumstances and reduce the need for collection of experimental data.     

Isolated iron-molybdenum cofactor of nitrogenase exists in multiple forms in its oxidized and semi-reduced states

Electrochemical and EPR spectroscopic experiments demonstrate that the isolated iron-molybdenum cofactor from the molybdenum-iron protein of nitrogenase from Azotobacter vinelandii exists in multiple forms in both its oxidized and semi-reduced states. The particular forms found in either oxidation state appear to be a function of the acid/base status of the solvent, N-methylformamide. In "alkaline" N-methylformamide, a single, detectable form of iron-molybdenum cofactor is observed for both oxidized and semi-reduced states. The semi-reduced form, termed R(s-r), is the one previously recognized with an S = 3/2 EPR spectrum with apparent g values of 4.6, 3.4, 2.0. Its oxidized counterpart, termed B(ox), is characterized electrochemically by a differential pulse voltammetric reduction peak at -0.37 V versus the normal hydrogen electrode. In "acidic" solvent, two distinct, previously unrecognized redox pairs of iron-molybdenum cofactor forms exist. The two semi-reduced forms, N(s-r) and W(s-r), are characterized by EPR spectra with g = 4.5, 3.6, 2.0 and g = 4.9, 3.1, 1.9, respectively. Their oxidized counterparts, A(ox) and C(ox), have differential pulse voltammetric reduction peaks at -0.32 and -0.43 V versus the normal hydrogen electrode, respectively. Manipulations of either the isolation protocol or the sample conditions affects both the type and distribution of forms present. Each form likely corresponds to a biologically significant state of the cofactor cluster within the protein.     

Active and inactive forms of the transition-state analog protease inhibitor leupeptin: explanation of the observed slow binding of leupeptin to cathepsin B and papain

Leupeptin and similar peptide argininal (arginine aldehyde) transition-state analog protease inhibitors exist in three covalent forms in aqueous solution, the leupeptin hydrate (IH), a cyclic carbinolamine form (IC) generated by the addition of the guanidino epsilon N to the aldehydic carbon, and the free aldehyde form (IA). 1H NMR in D2O show their equilibrium concentrations to be 42, 56, and 2% for IH, IC (R and S enantiomers), and IA. The rates of conversion of (formula; see text) were determined by 1H NMR in D2O by trapping IA with semicarbazide. Application of a deuterium isotope effect of 2.8 led to rate constants in H2O for kC of 0.092 min-1 and kD of 0.73 min-1. The equilibrium concentration of IA and rates for kC and kD are then used to explain the lag phase in the inhibition of cathepsin B and papain by leupeptin. Two circumstances are observed. (i) At micromolar concentrations of leupeptin and papain the binding of leupeptin is biphasic with rate constants identical to kD and kC. (ii) At more dilute nanomolar concentrations of total leupeptin and proteases, the observed lag phase for approach to steady-state inhibition (with rate constant k') is now explained by the low values of the koff rate constants (0.072 min-1 for cathepsin B and 0.024 min-1 for papain) together with the extremely low concentrations of the active inhibitor form IA, with k' = kon[IA] + koff. While kon[IA] is slow, the second-order rate constant kon is found to be quite fast, 1.2 x 10(7) M-1 s-1 for cathepsin B and 1.8 x 10(7) M-1 s-1 for papain. Thus, the binding of leupeptin to cathepsin B and papain may show a lag phase, but this is not due to slow binding.     

Heat treatment of ripening apples: Differential effects on physiology and biochemistry

Apples ( Malus domestica Borkh.) were heated for 4 days at 38°C immediately after harvest and then placed at 20°C for 7–10 days. Protein synthesis, ethylene production and fruit softening were reversibly inhibited by the heat treatment. Fruit respiration, membrane permeability and chlorophyll degradation in the fruit peel were enhanced during the treatment. The heat-treated apples ripened normally but more slowly than untreated apple We hypothesize that heat treatment differentially affects processes which normally increase simultaneously during fruit ripening, by inhibiting those processes which require tie novo protein synthesis and enhancing those that do not.