Two analogs of azaspiracid isolated from mussels, Mytilus edulis, involved in human intoxication in Ireland

Two new analogs of azaspiracid, azaspiracid-2 and azaspiracid-3, were isolated from mussels collected at Arranmore Island, Ireland in 1997 as additional causes of human intoxication. Their structures were determined to be 8-methylazaspiracid and 22-demethylazaspiracid, respectively by NMR and negative ion FAB CID MS/MS experiments.

Measuring the effectiveness of bioptic telescopes for persons with central vision loss

PURPOSE

1) To evaluate a vision rehabilitation program aimed at training persons with central vision loss to use a bioptic telescope for improving life skills, including driving and 2) to compare the outcomes of subjects who are given bioptic telescopes and training, with subjects who are prescribed telescopic lenses without training.

METHODS

Twenty-five subjects ranging in age from 16 to 78 years were included in the study. Each subject was randomized to one of three groups: Group 1 received bioptic telescopes and training during the first approximately 3-month-long period of the approximately 6-month-long study; Group 2 received lenses and training during the second approximately 3-month-long period of the study; and Group 3 received the lenses for approximately 3 months without any training. An assessment battery consisting of clinical vision tests, functional tasks evaluated by an orientation and mobility specialist, driving skills evaluated by a kinesiotherapist specializing in driver's education, and psychophysical measures was administered to Groups 1 and 2 at baseline, and at approximately 3 and 6 months, and to Group 3 at baseline and at approximately 3 months. The tasks were categorized into 6 major functional categories: Recognition, Mobility, Peripheral Identification, Scanning, Tracking, and Visual Memory. Training consisted of 5 weeks of laboratory-based training focusing on skills within these 6 categories, and 8 weeks of on-road driving training.

RESULTS

There was significant improvement in all task categories with use of the telescopes. There was improvement in all task groups with training, though a significant difference between the trained and untrained groups existed only in the Recognition, Peripheral Identification, and Scanning Categories, but not in Mobility, Tracking, or Visual Memory. When the tasks involving driving-related skills were analyzed separately, training also had a significant effect.

CONCLUSION

There was significant improvement in visual skills with the use of a bioptic telescope. This improvement was greater with training in the use of the lenses in a number of visual skills categories including driving-related skills.

Protein kinase C epsilon mediates up-regulation of N-type calcium channels by ethanol

Brief exposure to ethanol inhibits L-type and N-type voltage-gated calcium channels in neural cells. Although chronic ethanol exposure up-regulates the density and function of L-type channels via a protein kinase C (PKC) delta-dependent mechanism, the effect of prolonged ethanol exposure on N-type channels is not known. Using PC12 cells, we found that exposure to 25 to 150 mM ethanol for 0 to 8 days produced a time- and concentration-dependent increase in the density of binding sites for the N-type channel antagonist (125)I-omega-conotoxin GVIA. This was associated with an increase in omega-conotoxin GVIA-sensitive, depolarization-evoked rises in [Ca(2+)](i). Increases in (125)I-omega-conotoxin GVIA binding also were observed in the frontal cortex and the hippocampus, but not in the thalamus of mice exposed to ethanol vapor for 3 days. In PC12 cells, increases in (125)I-omega-conotoxin GVIA binding were blocked by the PKC inhibitor bisindolylmaleimide I and by expression of a selective peptide inhibitor of PKCepsilon. Expression of a selective inhibitor of PKCdelta did not alter ethanol-induced increases in (125)I-omega-conotoxin GVIA binding. These findings indicate that PKCepsilon mediates up-regulation of N-type channels by ethanol. Because N-type channels modulate calcium-dependent neurotransmitter release, these findings suggest a mechanism that may contribute to neuronal hyperexcitability observed during alcohol withdrawal.

Supersensitivity to allosteric GABA(A) receptor modulators and alcohol in mice lacking PKCepsilon

Several of the actions of ethanol are mediated by gamma-aminobutyrate type A (GABA(A)) receptors. Here we demonstrated that mutant mice lacking protein kinase C epsilon (PKCepsilon) were more sensitive than wild-type littermates to the acute behavioral effects of ethanol and other drugs that allosterically activate GABA(A) receptors. GABA(A) receptors in membranes isolated from the frontal cortex of PKCepsilon null mice were also supersensitive to allosteric activation by ethanol and flunitrazepam. In addition, these mutant mice showed markedly reduced ethanol self-administration. These findings indicate that inhibition of PKCepsilon increases sensitivity of GABA(A) receptors to ethanol and allosteric modulators. Pharmacological agents that inhibit PKCepsilon may be useful for treatment of alcoholism and may provide a non-sedating alternative for enhancing GABA(A) receptor function to treat other disorders such as anxiety and epilepsy.

A novel nociceptor signaling pathway revealed in protein kinase C epsilon mutant mice

There is great interest in discovering new targets for pain therapy since current methods of analgesia are often only partially successful. Although protein kinase C (PKC) enhances nociceptor function, it is not known which PKC isozymes contribute. Here, we show that epinephrine-induced mechanical and thermal hyperalgesia and acetic acid-associated hyperalgesia are markedly attenuated in PKCepsilon mutant mice, but baseline nociceptive thresholds are normal. Moreover, epinephrine-, carrageenan-, and nerve growth factor- (NGF-) induced hyperalgesia in normal rats, and epinephrine-induced enhancement of tetrodotoxin-resistant Na+ current (TTX-R I(Na)) in cultured rat dorsal root ganglion (DRG) neurons, are inhibited by a PKCepsilon-selective inhibitor peptide. Our findings indicate that PKCepsilon regulates nociceptor function and suggest that PKCepsilon inhibitors could prove useful in the treatment of pain.

Levels of alpha1-proteinase inhibitor and alpha2-macroglobulin in the tear film of patients with keratoconus

PURPOSE

Levels of alpha1-proteinase inhibitor and alpha2-macroglobulin in the tear film of patients with keratoconus were measured to elucidate their possible roles in the pathogenesis of keratoconus.

METHODS

Tear samples were collected from 15 keratoconus patients and 14 age-similar human control subjects. Levels of alpha1-proteinase inhibitor and alpha2-macroglobulin in each tear sample were quantified and compared between the two groups.

RESULTS

Mean values for alpha1-proteinase inhibitor were 101.0+/-35.5 and 106.1+/-41.7 ng/microg protein for the keratoconus and control groups, respectively. The corresponding mean values for alpha2-macroglobulin were 13.5+/-6.8 and 14.8+/-7.5 ng/microg protein. Neither inhibitor showed a statistically significant difference between the keratoconus and control specimens. Subset analysis to evaluate the effects of contact lens wear and the presence of a graft in the fellow eye did not reveal a statistically significant difference.

CONCLUSION

The tear film of patients with keratoconus contains normal levels of protease inhibitors. Therefore, the tear film may not be a source of the reduced inhibitor levels shown in the corneas of patients with keratoconus.

In vivo gene transfer of nitric oxide synthase enhances vasomotor function in carotid arteries from normal and cholesterol-Fed rabbits

BACKGROUND

The vascular endothelium is anatomically intact but functionally abnormal in preatherosclerotic states, and an early deficit in the bioavailability of nitric oxide (NO) or related molecules has been described in both humans and animal models. We hypothesized that the targeted gene transfer of NO synthase (NOS) isoforms might ameliorate or reverse the deficit.

METHODS AND RESULTS

We constructed a recombinant adenovirus, Ad.nNOS, that expresses the neuronal isoform of NOS (nNOS) and used it for in vivo endovascular gene transfer to carotid arteries (CA) from normal and cholesterol-fed rabbits. Vessels were harvested 3 days after gene transfer. In CA from normal rabbits, Ad.nNOS generated high levels of functional nNOS protein predominantly in endothelial cells and increased vascular NOS activity by 3.4-fold relative to sham-infected control CA. Ad.nNOS gene transfer also significantly enhanced endothelium-dependent vascular relaxation to acetylcholine; at 3 micromol/L acetylcholine, Ad.nNOS-treated arteries showed an 86+/-4% reduction in precontracted tension, whereas control CA showed a 47+/-6% reduction in tension. Contraction in response to phenylephrine and relaxation in response to nitroprusside were unaffected in both control and Ad.nNOS-treated CA. To determine the effect of Ad.nNOS in atherosclerotic arteries, 10 male New Zealand White rabbits maintained on a 1% cholesterol diet for 10 to 12 weeks underwent gene transfer according to the same protocol used in normal rabbits. Ad.nNOS-treated arteries showed a 2-fold increase in NADPH-diaphorase staining intensity relative to sham-infected and Ad. betaGal-treated arteries. The CA from cholesterol-fed rabbits showed impaired acetylcholine-induced relaxation, but this abnormality was almost entirely corrected by Ad.nNOS gene transfer.

CONCLUSIONS

In vivo adenovirus-mediated endovascular delivery of nNOS markedly enhances vascular NOS activity and can favorably influence endothelial physiology in the intact and atherosclerotic vessel wall.

Use of bioptic amorphic lenses to expand the visual field in patients with peripheral loss

PURPOSE

To test the effectiveness of a bioptic form of a peripheral vision-enhancement lens in patients with retinitis pigmentosa (RP), choroideremia, and Usher's syndrome Type II.

METHODS

Fifteen patients with peripheral visual field loss were trained in the use of the amorphic lenses for driving and other everyday activities for a 3-month period. A cross-over study design was used, where one group of eight patients received training during the first 3 months of the 6-month study, and another group of seven patients received training during the second 3 months. All patients were administered a battery of clinical, psychophysical, functional, mobility, and driving assessment tests at the beginning of the study, at 3 months, and at 6 months. The assessment tests were coded according to the primary visual skill involved in the task. These visual skills included: recognition, peripheral detection, scanning, tracking, visual memory, and mobility.

RESULTS

After training, the patients showed improvement in all visual skills categories on the assessment tests, with overall improvement of 37%. There was no significant difference in the levels of improvement between the two groups. Those with smaller visual field extents showed significantly greater improvement on peripheral detection and scanning tasks. Those patients trained during the first 3 months of the study maintained their skills when tested at the 6-month point.

CONCLUSION

Patients with peripheral vision loss may benefit from a rehabilitation program which combines low vision training with amorphic lenses in a bioptic configuration.

Protein kinase Cdelta mediates ethanol-induced up-regulation of L-type calcium channels

Brief ethanol exposure inhibits L-type, voltage-gated calcium channels in neural cells, whereas chronic exposure increases the number of functional channels. In PC12 cells, this adaptive response is mediated by protein kinase C (PKC), but the PKC isozyme responsible is unknown. Since chronic ethanol exposure increases expression of PKCdelta and PKCepsilon, we investigated the role these isozymes play in up-regulation of L-type channels by ethanol. Incubation with the PKC inhibitor GF 109203X or expression of a PKCdelta fragment that inhibits phorbol ester-induced PKCdelta translocation largely prevented ethanol-induced increases in dihydropyridine binding and K+-stimulated 45Ca2+ uptake. A corresponding PKCepsilon fragment had no effect on this response. These findings indicate that PKCdelta mediates up-regulation of L-type channels by ethanol. Remaining responses to ethanol in cells expressing the PKCdelta fragment were not inhibited by GF 109203X, indicating that PKCdelta-independent mechanisms also contribute. PKCdelta overexpression increased binding sites for dihydropyridine and L-channel antagonists, but did not increase K+-stimulated 45Ca2+ uptake, possibly because of homeostatic responses that maintain base-line levels of channel function. Since L-type channels modulate drinking behavior and contribute to neuronal hyperexcitability during alcohol withdrawal, these findings suggest an important role for PKCdelta in alcohol consumption and dependence.

Bronchodilator S-nitrosothiol deficiency in asthmatic respiratory failure

BACKGROUND

Nitric oxide (NO) gas concentrations are high in the expired air of individuals with asthma, but not consistently so in the expired air of people with pneumonia. S-nitrosothiols are naturally occurring bronchodilators, the concentrations of which are raised in the airways of patients with pneumonia. Airway S-nitrosothiols have not been studied in asthma.

METHODS

Tracheal S-nitrosothiol concentrations from eight asthmatic children in respiratory failure were compared with those of 21 children undergoing elective surgery.

RESULTS

Mean S-nitrosothiol concentrations in asthmatic children were lower than in normal children (65 [SD 45] nmol/L vs 502 [SD 429] nmol/L) and did not vary with inspired oxygen concentration or airway thiol concentration.

INTERPRETATION

Severe asthma is associated with low concentrations of airway S-nitrosothiols. This is the first reported deficiency of an endogenous bronchodilator in the human asthmatic airway lining fluid. We suggest that S-nitrosothiol metabolism may be a target for the development of new asthma therapies.

Protein kinase A regulates regulates inhibition of N- and P/Q-type calcium channels by ethanol in PC12 cells

Ethanol inhibits L-type Ca++ channels, but little is known about its effect on other voltage-gated Ca++ channels. To examine non-L-type channels we used nerve growth factor-differentiated PC12 cells treated with the L channel blocker nifedipine. Using selective Ca++ channel antagonists, we found that N-type and P/Q-type channels mediate most of the remaining depolarization-evoked Ca++ rise. Ethanol (10-150 mM) inhibited depolarization-induced rises in intracellular Ca++ with maximal inhibition of 46% achieved using 50 mM ethanol. Inhibition was time dependent, requiring at least 8 min to develop fully. Ethanol did not alter Ca++ mobilization, sequestration, extrusion or capacitative entry. Sp-adenosine cyclic 3',5'-phosphorothioate, a specific activator of protein kinase A (PKA), blocked inhibition by ethanol, whereas the protein kinase C activator phorbol 12-myristate, 13-acetate did not. Okadaic acid, an inhibitor of protein phosphatases type-1 and type-2A, also blocked inhibition by ethanol with an IC50 of 3 nM. This was prevented by inhibiting PKA, indicating that the action of okadaic acid was due to increased PKA-mediated phosphorylation. These results indicate that ethanol can inhibit N-type and P/Q-type channels and this is antagonized by activating PKA. The findings suggest the sensitivity of these channels to ethanol is regulated by a phosphoprotein that is a substrate for PKA and protein phosphatase type-2A.

An inhibitory fragment derived from protein kinase Cepsilon prevents enhancement of nerve growth factor responses by ethanol and phorbol esters

We have studied nerve growth factor (NGF)-induced differentiation of PC12 cells to identify PKC isozymes important for neuronal differentiation. Previous work showed that tumor-promoting phorbol esters and ethanol enhance NGF-induced mitogen-activated protein (MAP) kinase activation and neurite outgrowth by a PKC-dependent mechanism. Ethanol also increases expression of PKCdelta and PKCepsilon, suggesting that one these isozymes regulates responses to NGF. To examine this possibility, we established PC12 cell lines that express a fragment encoding the first variable domain of PKCepsilon (amino acids 2-144), which acts as an isozyme-specific inhibitor of PKCepsilon in cardiac myocytes. Phorbol ester-stimulated translocation of PKCepsilon was markedly reduced in these PC12 cell lines. In addition, phorbol ester and ethanol did not enhance NGF-induced MAP kinase activation or neurite outgrowth in these cells. In contrast, phorbol ester and ethanol increased neurite outgrowth and MAP kinase phosphorylation in cells expressing a fragment derived from the first variable domain of PKCdelta. These results demonstrate that PKCepsilon mediates enhancement of NGF-induced signaling and neurite outgrowth by phorbol esters and ethanol in PC12 cells.

Overexpression of epsilon-protein kinase C enhances nerve growth factor-induced phosphorylation of mitogen-activated protein kinases and neurite outgrowth

Protein kinase C (PKC) activation enhances neurite outgrowth in several cell lines and primary neurons. The PKC isozymes that mediate this response are unknown. One clue to their identity has come from studies using PC12 cells treated with ethanol. In these cells, ethanol increases levels of delta-PKC and epsilon-PKC and markedly enhances nerve growth factor (NGF)-induced neurite outgrowth and activation of mitogen-activated protein (MAP) kinases by a PKC-dependent mechanism. Since these findings suggest that delta-PKC or epsilon-PKC can promote neural differentiation, we studied neurite outgrowth in stably transfected PC12 cell lines that overexpress these isozymes. Overexpression of epsilon-PKC markedly increased NGF-induced neurite outgrowth. This effect was blocked by down-regulating PKC or by treating cells with the PKC inhibitor GF 109203X. In addition, overexpression of epsilon-PKC enhanced NGF-induced phosphorylation of MAP kinases. In contrast, overexpression of delta-PKC did not alter responses to NGF. These results demonstrate that epsilon-PKC promotes NGF-induced neurite outgrowth by enhancing NGF signal transduction. These findings suggest a role for epsilon-PKC in neural differentiation and plasticity.

Depolarization-induced neurite outgrowth in PC12 cells requires permissive, low level NGF receptor stimulation and activation of calcium/calmodulin-dependent protein kinase

Neuronal activity is required for normal neural development. Excessive activity can cause abnormal growth of neural processes and may contribute to formation of epileptic foci. Using PC12 cells, we investigated mechanisms by which depolarization regulates neurite growth. Depolarization with 45 mM KCl induced neurite outgrowth only if NGF receptors were partly activated by overexpression of p140trkA or by treatment with a low concentration of NGF that alone was insufficient to stimulate neurite formation. Depolarization-induced neurite growth was reduced by inhibitors of L-type Ca2+ channels, Ca2+/calmodulin-dependent protein (CaM) kinases II and IV, and transcription. These results identify a novel mechanism by which depolarizing stimuli synergize with subthreshold activation of NGF receptors to induce neurite growth through a Ca2+ and CaM kinase-dependent signal transduction pathway.

Construction of murine coronavirus mutants containing interspecies chimeric nucleocapsid proteins

Targeted RNA recombination was used to construct mouse hepatitis virus (MHV) mutants containing chimeric nucleocapsid (N) protein genes in which segments of the bovine coronavirus N gene were substituted in place of their corresponding MHV sequences. This defined portions of the two N proteins that, despite evolutionary divergence, have remained functionally equivalent. These regions included most of the centrally located RNA-binding domain and two putative spacers that link the three domains of the N protein. By contrast, the amino terminus of N, the acidic carboxy-terminal domain, and a serine- and arginine-rich segment of the central domain could not be transferred from bovine coronavirus to MHV, presumably because these parts of the molecule participate in protein-protein interactions that are specific for each virus (or, possibly, each host). Our results demonstrate that targeted recombination can be used to make extensive substitutions in the coronavirus genome and can generate recombinants that could not otherwise be made between two viruses separated by a species barrier. The implications of these findings for N protein structure and function as well as for coronavirus RNA recombination are discussed.

Protein kinase C isozymes that mediate enhancement of neurite outgrowth by ethanol and phorbol esters in PC12 cells

Using PC12 cells to study ethanol's effects on growth of neural processes, we found that ethanol enhances NGF- and basic FGF-induced neurite outgrowth. Chronic ethanol exposure selectively up-regulates delta and epsilon protein kinase C (PKC) and increases PKC-mediated phosphorylation in PC12 cells. Since PKC regulates differentiation, we investigated the role of PKC in enhancement of neurite outgrowth by ethanol. Like ethanol, 0.3-10 nM phorbol 12-myristate, 13-acetate (PMA) increased NGF-induced neurite outgrowth. However, higher concentrations did not, and immunoblot analysis demonstrated that 100 nM PMA markedly depleted cells of beta, delta and epsilon PKC. PMA (100 nM) also down-regulated beta, delta and epsilon PKC in ethanol-treated cells and completely prevented enhancement of neurite outgrowth by ethanol. In contrast, the cAMP analogue 8-bromoadenosine cAMP did not completely mimic the effects of ethanol on neurite outgrowth, and ethanol was able to enhance neurite formation in mutant PC12 cells deficient in protein kinase A (PKA). These findings implicate beta, delta or epsilon PKC, but not PKA, in the neurite-promoting effects of ethanol and PMA. Since chronic ethanol exposure up-regulates delta and epsilon, but not beta PKC, these findings suggest that delta or epsilon PKC regulate neurite outgrowth.

Simultaneous caries induction and calculus formation in rats

Weanling specific pathogen-free Osborne-Mendel rats were fed a high-calcium, high-phosphorus diet with various levels of sucrose and inoculated with Streptococcus sobrinus strain 6715-13WT and Actinomyces viscosus strain OMZ-105 in order to determine whether calculus and caries could develop simultaneously. Rats consumed diets designated RC-16-5, RC-16-25, or RC-16-50 which partially replaced the corn starch component with progressively higher levels of sucrose, thus, to 5, 25, or 50% sucrose. In general, bacterial recoveries of A. viscosus declined with higher sucrose content of the diet, but a pattern of recovery for S. sobrinus was less clear with respect to dietary sucrose. S. sobrinus, however, was recovered at higher percentages from the tooth surface flora at the later two of three sampling dates. Most calculus--identified by the brittle quality, staining characteristics, and apatitic x-ray diffraction patterns of tooth surface deposits--was formed on the maxillary molars, and most carious lesions occurred on mandibular molars. While there was minimal association of the calculus score with the amount of sucrose in the diet, calculus scores increased greatly from 23 to 43 days after infectious challenge. Caries scores, of both fissure and smooth surfaces, by contrast, increased in a dose-response fashion with increasing dietary sucrose and with time. It is thus possible to induce calculus formation and caries simultaneously in specific pathogen-free Osborne-Mendel rats consuming a high-calcium and -phosphorus diet conducive to calculus formation and containing sucrose.(ABSTRACT TRUNCATED AT 250 WORDS)

Young suicide attempters compared with a control group: psychological, affective, and attitudinal variables

Suicide attempters admitted to a general hospital psychiatric ward completed questionnaires to elicit information following their suicide attempt. Compared to normal controls who had never attempted suicide, suicide attempters were significantly more hopeless, depressed, and hostile. The suicide attempts seemed to occur in response to stress. A crisis intervention model was suggested as the most appropriate way of managing these patients.

Bicarbonate-based powder and paste dentifrice effects on caries

The effects of sodium bicarbonate-based powder and paste dentifrices on dental caries and Streptococcus sobrinus recoveries in rats were studied. Three S. sobrinus 6715-13WT infected groups of specific pathogen-free weanling rats, consuming a diet which contains 56% sucrose, were topically treated with either demineralized water, dentifrice paste, or dentifrice powder. Both the paste and powder contained 0.22% (w/w) NaF. All topical treatments were given for one min daily per rat, five days a week. Animals' teeth were swabbed for recovery of 6715-13WT and total recoverable flora. Recoveries of 6715-13WT were 75% lower from both powder-treated and paste-treated dentifrice than from water-treated rats' teeth (p less than 0.001). Total caries scores were 45% lower for the powder-treated and 43% lower for the paste-treated rats than the water-treated ones (p less than 0.01). The major portion of the caries inhibition was evident on smooth tooth surfaces, 68% for powder-treated and 65% for paste-treated by comparison with water-treated animals (p less than 0.01), although a lesser caries reduction was also evident in tooth fissures (sulci). Thus, both powder and paste formulations of a sodium bicarbonate-based dentifrice containing 0.22% NaF equally and potently inhibited caries in rats, challenged bacteriologically and dietarily to develop severe caries.

Bicarbonate-based dental powder, fluoride, and saccharin inhibition of dental caries associated with Streptococcus mutans infection of rats

The effects of NaHCO3-based dental powder containing NaF and sodium saccharin on dental caries and Streptococcus mutans recoveries in rats were studied. Weanling specific-pathogen-free Osborne-Mendel (SPFOM) rats were inoculated with S. mutans NCTC-10449S. Four infected groups were topically treated with either demineralized water (DW), a dental powder suspended such that there was 1 part solid per 2 parts DW, 0.073% NaF, or a combination of 0.073% NaF and 0.5% Na-saccharin (Nas). NaF-supplemented DW (at 10 ppm F-) was provided to a 5th group of infected rats as a positive treatment control, but this group was otherwise untreated. A sixth but uninfected group was topically treated with DW. All topical treatments were given once for 1 min daily per rat, for 5 days per week. Animals' teeth were swabbed for recovery of 10449S and total recoverable flora. Recoveries of 10449S were lower from powder-treated rats than from DW-treated rats. This difference approached but did not reach statistical significance. Total caries scores were 51% lower for the dental powder, 36% lower for the topical NaF, 34% lower for the combined NaF-Nas, and 54% lower for the NaF-supplemented drinking water group, all p less than 0.001. While all of the treatments inhibited smooth-surface caries, the dental powder effects, like those for the combined NaF-Nas, and NaF drinking water, were evident in fissure tooth surfaces as well.(ABSTRACT TRUNCATED AT 250 WORDS)

Who provides patients with drug information?

One hundred and fifty four patients were interviewed to determine the type and source of information that they had received about drugs that had been prescribed for them. Most had been told how often to take the drugs (145 (94%)) and how much to take each time (143 (93%)), but few had been informed about side effects (49 (32%)) and fewer had received written information (22 (14%)). Pharmacists most commonly supplied information about how often to take the drugs (105 (68%)), how much to take each time (99 (64%)), and the best way to take it (109 (71%)). Doctors most often gave information about duration of treatment (116 (75)) and possible side effects (126 (82%)). Few patients requested specific information on their own initiative. More research is needed to determine how best to communicate drug information to patients.

Radiation damage to the brain: neuropsychiatric aspects

Although radiation necrosis of the brain is a recognized complication of irradiation of the central nervous system, the psychiatric aspects of this phenomenon are less well defined. Two cases of radiation necrosis in which psychiatric symptoms were a prominent part of the clinical picture are presented. Factors that determine the evolution and clinical presentation of radiation necrosis are reviewed. In particular, the role of the consultation psychiatrist in the diagnosis and management of such patients is discussed.

Bipolar affective symptoms associated with use of captopril and abrupt withdrawal of pargyline and propranolol

A woman with a family history but no personal history of depression developed bipolar symptoms associated with manipulations of her antihypertensive regimen. The author discusses hypotheses regarding the effects of these manipulations and the implications for treatment.

The use of DSM-III in a general hospital consultation-liaison service

Eighteen months' use of DSM-III by a consultation-liaison service in a university hospital is reported. DSM-III's multiaxial system seems to be feasible and revealing, but presents some problems. Adjustment Disorder and Organic Mental Disorders were the most frequent Axis I diagnoses. Approximately one-fourth of the patients received an Axis II diagnosis and 85% received an Axis III diagnosis. In 70% of the patients there was both a psychiatric diagnosis (on Axis I or II) and a physical disorder (on Axis III). On Axis IV and V, this population appeared to be under moderate to severe psychosocial stress and had, as a group, a fair or better level of previous adaptive functioning. The possible significance of these findings and potential areas for further refinements and investigations are discussed.

Psychiatry--family practice liaison: a collaborative approach to clinical training

In view of the growing need for effective liaison between psychiatry and family practice programs, some of the models for educational and clinical liaison are discussed, and a clinical training program is described in which psychiatry and family practice educators work collaboratively in the training of both family practice and psychiatry residents and medical students. The program is offered as a model for providing comprehensive clinical training to residents and students and comprehensive clinical care to patients.

Losses in multimode hollow metal infrared waveguides

Experimental measurements of loss in a hollow metal waveguide show quantitative agreement with the multimode theory of losses using a complex refractive index.

Propagation of infrared light in flexible hollow waveguides

Designs are described for flexible hollow waveguides with low ir loss over distances on the order of 1 m. Transmission losses at 10.6 microm are calculated, and the effect of bends and twists is discussed. A hollow combination metal-dielectric-walled rectangular waveguide is proposed that can have transmission as high as 95% for a 1-m length, while bent with a 1-m radius of curvature.

Size and shape in biology

Arguments based on elastic stability and flexure, as opposed to the more conventional ones based on yield strength, require that living organisms adopt forms whereby lengths increase as the (2/3) power of diameter. The somatic dimensions of several species of animals and of a wide variety of trees fit this rule well. It is a simple matter to show that energy metabolism during maximal sustained work depends on body cross-sectional area, not total body surface area as proposed by Rubner (1) and many after him. This result and the result requiring animal proportions to change with size amount to a derivation of Kleiber's law, a statement only empirical until now, correlating the metabolically related variables with body weight raised to the (3/4) power. In the present model, biological frequencies are predicted to go inversely as body weight to the (1/4) power, and total body surface areas should correlate with body weight to the (5/8) power. All predictions of the proposed model are tested by comparison with existing data, and the fit is considered satisfactory. In The Fire of Life, Kleiber (5) wrote "When the concepts concerned with the relation of body size and metabolic rate are clarified, . . . then compartive physiology of metabolism will be of great help in solving one of the most intricate and interesting problems in biology, namely the regulation of the rate of cell metabolism." Although Hill (23) realized that "the essential point about a large animal is that its structure should be capable of bearing its own weight and this leaves less play for other factors," he was forced to use an oversimplified "geometric similarity" hypothesis in his important work on animal locomotion and muscular dynamics. It is my hope that the model proposed here promises useful answers in comparisons of living things on both the microscopic and the gross scale, as part of the growing science of form, which asks precisely how organisms are diverse and yet again how they are alike.