Structural parts involved in activation and inactivation of the sodium channel

Structure-function relationships of the sodium channel expressed in Xenopus oocytes have been investigated by the combined use of site-directed mutagenesis and patch-clamp recording. This study provides evidence that the positive charges in segment S4 are involved in the voltage-sensing mechanism for activation of the channel and that the region between repeats III and IV is important for its inactivation.

Inhibition of Bax channel-forming activity by Bcl-2

Proteins of the Bcl-2 family are intracellular membrane-associated proteins that regulate programmed cell death (apoptosis) either positively or negatively by as yet unknown mechanisms. Bax, a pro-apoptotic member of the Bcl-2 family, was shown to form channels in lipid membranes. Bax triggered the release of liposome-encapsulated carboxyfluorescein at both neutral and acidic pH. At physiological pH, release could be blocked by Bcl-2. Bcl-2, in contrast, triggered carboxyfluorescein release at acidic pH only. In planar lipid bilayers, Bax formed pH- and voltage-dependent ion-conducting channels. Thus, the pro-apoptotic effects of Bax may be elicited through an intrinsic pore-forming activity that can be antagonized by Bcl-2.

Biological activity of chitosan: ultrastructural study

Reparative processes are reconstructive phenomena in which cellular elements and extracellular matrix glycoproteins interact to build the injured tissue. Biomaterials can be used to improve or stimulate reconstruction. In the present experimental investigation, tissue repair induced by chitosan, an 86.8% deacetylated poly(GlcNAc), was monitored by morphological analysis. To evaluate its biological role, chitosan was positioned in contact with dura mater or was used as a dura mater substitute. This polysaccharide, having structural characteristics similar to glycosaminoglycans, seems to mimic their functional behaviour. The inductive and stimulatory activity of chitosan on connective tissue-rebuilding is clearly demonstrated, and it is suggested that chitosan could be considered a primer on which a normal tissue architecture is organized.

Mapping the site of block by tetrodotoxin and saxitoxin of sodium channel II

The SS2 and adjacent regions of the 4 internal repeats of sodium channel II were subjected to single mutations involving, mainly, charged amino acid residues. These sodium channel mutants, expressed in Xenopus oocytes by microinjection of cDNA-derived mRNAs, were tested for sensitivity to tetrodotoxin and saxitoxin and for single-channel conductance. The results obtained show that mutations involving 2 clusters of predominantly negatively charged residues, located at equivalent positions in the SS2 segment of the 4 repeats, strongly reduce toxin sensitivity, whereas mutations of adjacent residues exert much smaller or no effects. This suggests that the 2 clusters of residues, probably forming ring structures, take part in the extracellular mouth and/or the pore wall of the sodium channel. This view is further supported by our finding that all mutations reducing net negative charge in these amino acid clusters cause a marked decrease in single-channel conductance.

Subthreshold behavior and phenomenological impedance of the squid giant axon

The oscillatory behavior of the cephalopod giant axons in response to an applied current has been established by previous investigators. In the study reported here the relationship between the familiar "RC" electrotonic response and the oscillatory behavior is examined experimentally and shown to be dependent on the membrane potential. Computations based on the three-current system which was inferred from electrical measurements by Hodgkin and Huxley yield subthreshold responses in good agreement with experimental data. The point which is developed explicitly is that since the three currents, in general, have nonzero resting values and two currents, the "Na" system and the "K" system, are controlled by voltage-dependent time-variant conductances, the subthreshold behavior of the squid axon in the small-signal range can be looked upon as arising from phenomenological inductance or capacitance. The total phenomenological impedance as a function of membrane potential is derived by linearizing the empirically fitted equations which describe the time-variant conductances. At the resting potential the impedance consists of three structures in parallel, namely, two series RL elements and one series RC element. The true membrane capacitance acts in parallel with the phenomenological elements, to give a total impedance which is, in effect, a parallel R, L, C system with a "natural frequency" of oscillation. At relatively hyperpolarized levels the impedance "degenerates" to an RC system.

Pursuing the structure and function of voltage-gated channels

A cyclical process of experimentation and theoretical analysis is being used to develop increasingly precise models of the structure and functional mechanisms of membrane proteins. Nucleic acid sequences have been determined for several voltage-gated sodium, calcium and potassium channels from invertebrates and vertebrates and from nerve and muscle tissues. Some of these sequences have been altered using site-directed mutagenesis. Properties of channels expressed after injection of normal and altered mRNA into Xenopus oocytes have been analysed by a variety of patch-clamp techniques. Preliminary structural models based on the first sequence information on sodium channels need to be modified to account for a large amount of new data. Here, Robert Guy and Franco Conti present their current view of the activation mechanism and ion selectivity of the voltage-gated channels.

Potassium and sodium ion current noise in the membrane of the squid giant axon

1. The spectral density of current noise power from 20 mm segments of giant axons of the squid Loligo vulgaris has been measured under space-clamp and voltage-clamp conditions. From 4 to 1000 Hz the measured noise is larger by several orders of magnitude than the theoretical thermal noise. The amplifier's noise, which may yield appreciable contributions above 200 Hz, could be evaluated and subtracted from the total noise using direct measurements of the membrane impedance...

Soybean-protein diet in the treatment of type-II hyperlipoproteinaemia

A soybean textured protein induced a 14% decrease of plasma-cholesterol levels after two weeks and 21% after three when substituted for animal proteins in a group of 20 patients with type-II hyperlipoproteinaemia. Comparison of soybean diet with a standard low-lipid diet in the same patients, according to a cross-over protocol, indicated that this hypocholesterolaemic effect was not due to differences in the lipid composition of the two diets. The hypothesis that a soy protein has a hypocholesterolaemic action per se is supported by the results of a subsequent experiment in 8 type-II patients in whom the addition of cholesterol (500 mg/day) to soy protein did not modify the hypocholesterolaemic response.

Single channel recordings of K+ currents in squid axons

Ionic currents from individual K+ channels in squid axon membrane have been recorded. At hyperpolarizing membrane voltages, unit events occur as widely spaced rectangular pulses with short interruptions. The frequency of occurrence of the units increases strongly when the membrane is depolarized.

Generating diversity at GABAergic synapses

GABA-mediated transmission is characterized by high variability of synaptic responses. Major contributors to this variability are: presynaptic factors, including release probability and number of release sites; factors that determine synaptic GABA transients in the cleft, including diffusion and the actions of GABA transporters; and postsynaptic factors, including GABA(A) receptors subtypes, their location and number, their modulation by endogenous and exogenous factors, and their interactions with postsynaptic-anchoring proteins.

Characterization of antisera to glutamate and aspartate

Antisera were raised in rabbits against glutamate (Glu) and aspartate (Asp) conjugated to the invertebrate carrier protein hemocyanin (HC) with glutaraldehyde (GA). The antisera were characterized by testing their immunocytochemical staining properties on sections cut at the level of the ventral cochlear nucleus (VCN) from fixed brains of normal rats after absorption with conjugates of compounds structurally similar and biologically relevant to Glu and Asp. Optimal staining with Glu antiserum was obtained at a dilution of 1:10,000 and was completely blocked by 303 micrograms/ml of the Glu-HC conjugate. No crossreactivity with any of 11 compounds tested was observed. Optimal staining with the Asp antiserum was obtained at 1:8000 dilution and was completely blocked by 225 micrograms/ml of the Asp-HC conjugate. Of 10 compounds tested for crossreactivity, only L-asparagine demonstrated a measurable (about 10%) crossreactivity with the Asp antiserum. The specificity of the two antisera was also tested by immunoblot analysis against 11 compounds conjugated to HC with GA. Listed in order of staining intensity, from greatest to least, conjugates that reacted with the Glu antiserum were Glu greater than Gly-Glu greater than Asp-Glu = Asp greater than N-carbamyl (NC)-Glu greater than Asn = Gln = GABA. Conjugates that reacted with the Asp antiserum, in order of decreasing staining intensity, were Asp greater than Glu-Asp = Asn greater than Gly-Asp greater than Glu. No other compounds tested for crossreactivity reacted with the two antisera in the immunoblot analysis. Glu-like immunoreactivity in rat dorsal root ganglia and somatosensory cortex, and the comparative distribution of Glu- and Asp-like immunoreactivities in the latter tissue, are presented as examples of staining patterns obtained with the two antisera.

EAAC1, a high-affinity glutamate tranporter, is localized to astrocytes and gabaergic neurons besides pyramidal cells in the rat cerebral cortex

High-affinity uptake of glutamate from the synaptic cleft plays a crucial role in regulating neuronal activity in physiological and pathological conditions. We have used affinity-purified specific polyclonal antibodies raised against a synthetic peptide corresponding to the C-terminal region of rabbit and rat EAAC1, a glutamate (Glu) transporter believed to be exclusively neuronal, to investigate its cellular and subcellular localization and whether it is expressed exclusively in glutamatergic cells of infragranular layers, as suggested by previous studies. Light microscopic studies revealed that EAAC1 immunoreactivity (ir) is localized to neurons and punctate elements in the neuropil. EAAC1-positive neurons were more numerous in layers II-III and V-VI, i.e. throughout all projection layers. Most EAAC1-positive neurons were pyramidal, although nonpyramidal cells were also observed. Some EAAC1-positive non-pyramidal neurons stained positively with an antiserum to GAD, thus demonstrating that EAAC1 is not confined to glutamatergic neurons. Non-neuronal EAAC1-positive cells were also observed in the white matter, and some of them stained positively with an antiserum to GFAP. Ultrastructural studies showed that EAAC1-ir was in neuronal cell bodies, dendrites and dendritic spines, but not in axon terminals, i.e. exclusively postsynaptic. Analysis of the type of axon terminals synapsing on EAAC1-ir profiles showed that 97% of them formed asymmetric contacts, thus indicating that EAAC1 is located at the very sites of excitatory amino acid release. Unexpectedly, EAAC1-ir was also found in a few astrocytic processes located in both the gray and the white matter. The localization of EAAC1 may explain the pathological symptoms that follow EAAC knockout (seizures and mild toxicity), as seizures could be due to the loss of EAAC1-mediated fine regulation of neuronal excitability at axodendritic and axospinous synapses, whereas the mild toxicity may be related to the functional inactivation of astrocytic EAAC1.

Disposition of metformin (N,N-dimethylbiguanide) in man

Kinetic parameters of metformin (N,N-dimethylbiguanide), an anti-diabetic reported to be associated with a lower number of episodes of lactic acidosis than phenformin, were determined in volunteers with normal renal function and in patients with different degrees of renal impairment. Drug in body fluids was measured by a highly specific and sensitive mass fragmentographic method, after the formation of a triazine derivative, obtained with heptafluorobutyric anhydride. The half-life (t 1/2) for the elimination of drug from plasma after intravenous injection in 5 normal subjects (1.52 +/- 0.3 hr) (mean +/- SD) was shorter than that reported for phenformin by a similar assay method (7 to 15 hr). The mean t 1/2 in 5 renal patients was 4.94 +/- 1.11 hr, and a correlation was observed between t 1/2 of drug from plasma and creatinine clearance. After oral administration of metformin tablets, drug recovery in urines was only 37.6%, possibly not as a consequence of low bioavailability (a similar low recovery was found after oral administration of the metformin solution used for the intravenous studies), but of binding to the intestinal wall, as shown in animal and clinical studies with metformin and other biguanides. Metformin is rapidly eliminated through active secretion by the kidney (mean renal clearance, 440.8 ml/min)--it is neither metabolized nor protein bound in plasma. The very brief plasma t 1/2 makes significant cumulation, with a standard tid regimen, unlikely. These findings may help explain the lower incidence of toxic effects, particularly lactic acidosis, than after phenformin.

Shaping excitation at glutamatergic synapses

Glutamatergic synapses vary, exhibiting EPSCs of widely different magnitudes and timecourses. The main contributors to this variability are: presynaptic factors, including release probability, quantal content and vesicle composition; factors that modulate the concentration and longevity of glutamate in the cleft, including diffusion and the actions of glutamate transporters; and postsynaptic factors, including the types and locations of ionotropic glutamate receptors, their numbers, and the nature and locations of associated intracellular signalling systems.

The muscle chloride channel ClC-1 has a double-barreled appearance that is differentially affected in dominant and recessive myotonia

Single-channel recordings of the currents mediated by the muscle Cl- channel, ClC-1, expressed in Xenopus oocytes, provide the first direct evidence that this channel has two equidistant open conductance levels like the Torpedo ClC-0 prototype. As for the case of ClC-0, the probabilities and dwell times of the closed and conducting states are consistent with the presence of two independently gated pathways with approximately 1.2 pS conductance enabled in parallel via a common gate. However, the voltage dependence of the common gate is different and the kinetics are much faster than for ClC-0. Estimates of single-channel parameters from the analysis of macroscopic current fluctuations agree with those from single-channel recordings. Fluctuation analysis was used to characterize changes in the apparent double-gate behavior of the ClC-1 mutations I290M and I556N causing, respectively, a dominant and a recessive form of myotonia. We find that both mutations reduce about equally the open probability of single protopores and that mutation I290M yields a stronger reduction of the common gate open probability than mutation I556N. Our results suggest that the mammalian ClC-homologues have the same structure and mechanism proposed for the Torpedo channel ClC-0. Differential effects on the two gates that appear to modulate the activation of ClC-1 channels may be important determinants for the different patterns of inheritance of dominant and recessive ClC-1 mutations.

Channel noise in nerve membranes and lipid bilayers

The basic principles underlying fluctuation phenomena in thermodynamics have long been understood (for reviews see Kubo, 1957; Kubo, Matsuo & Kazuhiro 1973 Lax, 1960). Classical examples of how fluctuation analysis can provide an insight into the corpuscular nature of matter are the determination of Avogadro's number according to Einstein's theory of Brownian motion (see, e.g. Uhlenbeck & Ornstein, 1930; Kac, 1947) and the evaluation of the electronic charge from the shot noise in vacuum tubes (see Van der Ziel, 1970).

Measurement of the conductance of the sodium channel from current fluctuations at the node of Ranvier

Single myelinated nerve fibres of Rana esculenta were investigated under voltage clamp conditions at 13 degrees C. Fluctuations of steady-state membrane current were measured during the last 152 msec of 190-225 msec pulses depolarizing the membrane by 8-48 mV. Noise power spectral densities were calculated in the frequency range of 6-6-6757 Hz. 2. External application of 150 nM tetrodotoxin (TTX) and/or 10 mM tetraethylammonium (TEA) ion reduced the current fluctuations. The difference of current noise spectra measured in the presence and absence of TTX (TEA) was not changed by the presence of TEA (TTX) during both measurements, and was taken as the spectrum of the Na (K) current fluctuations. 3. Residual current noise during application of both TTX and TEA was, except for some excess noise at the low and high frequency ends of the spectrum, similar to the noise measured from a passive nerve model and could be understood in terms of Nyquist noise of the known resistances and the amplifier noise. 4. Na current fluctuation spectra were interpreted as the sum N/f+SNa(f) where SNa(F) represents the spectrum expected for a set of equal, independent Na channels with only two conductance states (open or closed) which follow Hodgkin-Huxley kinetics. With values of hinfinity, tauh and minfinity measured from macroscopic Na currents, the measured spectra were fitted well by optimizing N, SNa(0) and taum. Values of taum obtained by this method were in fair agreement with values found from macroscopic currents. 5. The 1/f component of Na current noise was roughly proportional to the square of the steady-state Na current, I2. The mean value of N/I2 was (1-1 +/- 0-3) X 10(-4). 6. The current carried by a single Na channel was calculated from fitted spectra and steady-state Na currents measured simultaneously with the current fluctuations. The single channel conductance gamma normalized to zero absolute membrane potential was calculated. The average gamma from twelve measurements at depolarizations of 8-40 mV was 7-9 +/- 0-9 pS (S.E. of mean). The apparent value of gamma was smallest with small depolarizations. Variations of the assumed kinetic properties of the model did not drastically affect the single channel conductance. 7. External application of 0-1 mM-Ni ion lengthened taum in the macroscopic currents and in the fluctuation spectra and enhanced both the steady-state Na current and the current fluctuations. In Ni-treated nodes gamma was smaller than in normal nodes.

Safety and efficacy of raltegravir in HIV-infected transplant patients cotreated with immunosuppressive drugs

Solid organ transplantations (SOT) are performed successfully in selected HIV-infected patients. However, multiple and reciprocal drug-drug interactions are observed between antiretroviral (ARV) drugs and calcineurin inhibitors (CNIs) through CYP450 metabolization. Raltegravir (RAL), a novel HIV-1 integrase inhibitor, is not a substrate of CYP450 enzymes. We retrospectively reviewed the outcomes of 13 HIV-infected transplant patients treated by an RAL + two nucleosidic reverse transcriptase inhibitor (NRTI) regimen, in terms of tolerability, ARV efficacy (plasma viral load, CD4 cell count), drug interactions, RAL pharmacokinetics and transplant outcome. Thirteen patients with liver (n = 8) or kidney (n = 5) transplantation were included. RAL was initiated (400 mg BID) either at time of transplantation (n = 6), or after transplantation (n = 7). Median RAL trough concentration was 507 ng/mL (176-890), which is above the in vitro IC95 for wild type HIV-1 strains (15 ng/mL). Target trough levels of CNIs were promptly obtained with standard dosages of tacrolimus or cyclosporine. RAL tolerability was excellent. There was no episode of acute rejection. HIV infection remained controlled. After a median follow-up of 9 months (range: 6-14), all patients were alive with satisfactory graft function. The use of an RAL + two NRTI-based regimen is a good alternative in HIV-infected patients undergoing SOT.

Conductance of the sodium channel in myelinated nerve fibres with modified sodium inactivation

1. Na current fluctuations in nodes of Ranvier were measured under voltage clamp conditions as described in the preceding paper (Conti, Hille, Neumcke, Nonner & Stämpfli, 1976) and analysed in terms of power spectral density calculated for frequencies between 30 Hz and 5 kHz. 2. External (10(-5) g/ml.) Leiurus scorpion venom or Anemonia Toxin II (3 X 10(-5) g/ml.) or internal 20 mM iodate were applied in order to remove or slow down inactivation in part of the Na channels. The treatment increased the steady-state Na current during the noise measurement one-to eight fold over that in normal fibres. 3. Noise spectra were interpreted as the sum of 1/f noise and noise SNa(f) due to all-or-none, open-close transitions of single Na channels. The drug effects on the inactivation could be accounted for either by assuming two populations of channels, one with and one without inactivation, or by postulating a single population with modified inactivation characteristics. 4. Except for an increase in amplitude, the fluctuation spectra SNa(f) were similar to the ones in normal nodes. Again, the time constants taum obtained from the fit of the spectra agreed within a factor of 2 with the values of taum found in the macroscopic Na currents. 5. From the fluctuation spectra, single Na channel conductances gamma of 5-4 +/- 0-4 pS (iodate), 6-7 +/- 0-5 pS (Leiurus) and 7-0 +/- 0-6 pS (Anemonia) were calculated. The value of gamma was not significantly voltage dependent. 6. Our observations indicate that inactivation of Na channels can be modified with at most small effects on the microscopic properties of the activation process and on the conductance of the open channel. They suggest that the h mechanism normally produces all-or-none, open-close changes of conductance.

Randomized prospective clinical trial of high-dose epirubicin and dexrazoxane in patients with advanced breast cancer and soft tissue sarcomas

PURPOSE

We conducted a randomized trial to evaluate primarily the cardioprotective effect of dexrazoxane (DEX) in patients with advanced breast cancer and soft tissue sarcomas (STS) treated with high-dose epirubicin (EPI). We wished also to determine the value of radioimmunoscintigraphy (RIS) in the assessment of anthracycline cardiotoxicity.

PATIENTS AND METHODS

Patients with breast cancer (n = 95) or STS (n = 34) received EPI 160 mg/m2 by intravenous (I.V.) bolus every 3 weeks with or without DEX 1,000 mg/m2 I.V. Cardiac monitoring included multigated radionuclide (MUGA) scans with determination of resting left ventricular ejection fraction (LVEF), and RIS with indium 111 antimyosin monoclonal antibodies.

RESULTS

In either disease, antitumor response rates, time to progression, and survival did not significantly differ between the two arms. There was little difference in noncardiac toxicity for the two treatment groups. All methods of cardiac evaluation clearly documented the cardioprotective effect of DEX. Four patients developed congestive heart failure (CHF), all in the EPI arm. The decrease in LVEF from baseline was significantly greater in the control group. An abnormal antimyosin uptake was observed early in both arms and progressively increased during treatment. However, this increase was significantly higher in the EPI group (P = .004).

CONCLUSION

DEX significantly protects against the development of cardiotoxicity when high single doses of EPI are used. Apparently, there was no evidence of an adverse impact of DEX on antitumor activity. Although RIS is a sensitive technique in detecting anthracycline cardiac damage, its specificity is low and it cannot be considered a primary test for guiding anthracycline treatment.

Neuronal and glial localization of GAT-1, a high-affinity gamma-aminobutyric acid plasma membrane transporter, in human cerebral cortex: with a note on its distribution in monkey cortex

High-affinity gamma-aminobutyric (GABA) plasma membrane transporters (GATs) influence the action of GABA, the main inhibitory neurotransmitter in the human cerebral cortex. In this study, the cellular expression of GAT-1, the main cortical GABA transporter, was investigated in the human cerebral cortex by using immunocytochemistry with affinity-purified polyclonal antibodies directed to the C-terminus of rat GAT-1. In temporal and prefrontal association cortex (Brodmann's areas 21 and 46) and in cingulofrontal transition cortex (area 32), specific GAT-1 immunoreactivity (ir) was localized to numerous puncta and fibers in all cortical layers. GAT-1+ puncta were distributed homogeneously in all cortical layers, although they were slightly more numerous in layers II-IV, and appeared to have a preferential relationship to the somata and proximal dendrites of unlabeled pyramidal cells, even though, in many cases, they were also observed around nonpyramidal cells. Electron microscopic observations showed that GAT-1+ puncta were axon terminals that formed exclusively symmetric synapses. In addition, some distal astrocytic processes also contained immunoreaction product. Analysis of the patterns of GAT-1 labeling in temporal and prefrontal association areas (21 and 46), in cingulofrontal transition areas (32), and in somatic sensory and motor areas (1 and 4) of the monkey cortex revealed that its distribution varies according to the type of cortex examined and indicated that the distribution of GAT-1 is similar in anatomically corresponding areas of different species. The present study demonstrates that, in the human homotypical cortex, GAT-1 is expressed by both inhibitory axon terminals and astrocytic processes. This localization of GAT-1 is compatible with a major role for this transporter in GABA uptake at GABAergic synapses and suggests that GAT-1 may contribute to determining GABA levels in the extracellular space.

Expression of NR1 and NR2A/B subunits of the NMDA receptor in cortical astrocytes

Ionotropic glutamate (Glu) receptors of the N-methyl-D-aspartate type (NMDA) play a fundamental role in many cortical functions. Native NMDA receptors are composed of a heteromeric assembly of different subunits belonging to two classes: NMDAR1 (NR1) and NMDAR2 (NR2). To date, NMDA receptors are believed to be expressed only in neurons, although electrophysiological and in situ hybridization studies have suggested that this class of Glu receptors might be also expressed by some astrocytes. In this study, we have investigated in the cerebral cortex of adult rats the presence of astrocytes expressing NR1 and NR2A/B subunits by immunocytochemistry with specific antibodies, and we show that some distal astrocytic processes, but only rarely astrocytic cell bodies, contain immunoreaction product indicative of NR1 and NR2A/B expression. These findings suggest that at least part of the role NMDA has in cortical functions might depend on the activation of astrocytic NMDA receptors; the subcellular localization of NR1 and NR2A/B subunits in distal processes suggests that NMDA receptors contribute to monitoring Glu levels in the extracellular space.

Clinical experience with the soybean protein diet in the treatment of hypercholesterolemia

The efficacy of the total substitution of animal proteins with a textured soybean protein in hypercholesterolemic individuals was assayed in 42 in-patients and 18 out-patients. The in-patients studied followed one of three different crossover protocols: in protocol A, the soybean diet was compared with a standard low lipid diet; protocol B compared two soybean diets, one with added cholesterol, one without; and protocol C compared a soybean diet containing a high P/S fatty acid ratio to one with a low P/S ratio. In all three protocols, the soybean regimen provided valid and reproducible hypocholesterolemic effects that were not modified by the addition of cholesterol. P/S variations appeared, however, to modify the final effect: soybean definitely had a decreased effectiveness with a low P/S (0.1) regimen. The overall plasma cholesterol changes in the 42 in-patients after 3 weeks on the different soybean diet protocols was -20%. Patients with type IIA and IIB hypercholesterolemia provided almost equivalent results, whereas patients with mixed phenotypes (IIB-III) appeared somewhat more sensitive to the dietary effect. Cholesterol decreased mostly in the low density lipoprotein fraction, but some very low density lipoprotein changes were also noted upon variation of the P/S ratio. The out-patients studied provided less satisfactory results. possibly due to the difficulty of adequately complying with the diet. These studies indicate that treatment with the soybean diet is an effective regimen for inducing a significant cholesterol reduction in type II patients refractory to standard low lipid regimens.