Undiagnosed Cirrhosis and Hepatic Encephalopathy in a National Cohort of Veterans With Dementia

Importance

Dementia and hepatic encephalopathy (HE) are challenging to distinguish clinically. Undiagnosed cirrhosis in a patient with dementia can lead to missed opportunities to treat HE.

Objective

To examine the prevalence and risk factors of undiagnosed cirrhosis and therefore possible HE in veterans with dementia.

Design, Setting, and Participants

A retrospective cohort study was conducted between 2009 and 2019 using data from the Veterans Health Administration (VHA) and 2 separate validation cohorts from the Richmond Veterans Affairs Medical Center. Data analysis was conducted from May 20 to October 15, 2023. Participants included 177 422 US veterans with a diagnosis of dementia at 2 or more clinic visits, no prior diagnosis of cirrhosis, and with sufficient laboratory test results to calculate the Fibrosis-4 (FIB-4) score.

Exposures

Demographic and clinical characteristics.

Main Outcomes and Measures

An FIB-4 score (>2.67 suggestive of advanced fibrosis and >3.25 suggestive of cirrhosis), capped at age 65 years even for those above this cutoff who were included in the analysis.

Results

Among 177 422 veterans (97.1% men; 80.7% White; mean (SD) age, 78.35 [10.97] years) 5.3% (n = 9373) had an FIB-4 score greater than 3.25 and 10.3% (n = 18 390) had an FIB-4 score greater than 2.67. In multivariable logistic regression models, FIB-4 greater than 3.25 was associated with older age (odds ratio [OR], 1.07; 95% CI, 1.06-1.09), male gender (OR, 1.43; 95% CI, 1.26-1.61), congestive heart failure (OR, 1.48; 95% CI, 1.43-1.54), viral hepatitis (OR, 1.79; 95% CI, 1.66-1.91), Alcohol Use Disorders Identification Test score (OR, 1.56; 95% CI, 1.44-1.68), and chronic kidney disease (OR, 1.11; 95% CI, 1.04-1.17), and inversely associated with White race (OR, 0.79; 95% CI, 0.73-0.85), diabetes (OR, 0.78; 95% CI, 0.73-0.84), hyperlipidemia (OR, 0.84; 95% CI, 0.79-0.89), stroke (OR, 0.85; 95% CI, 0.79-0.91), tobacco use disorder (OR, 0.78; 95% CI, 0.70-0.87), and rural residence (OR, 0.92; 95% CI, 0.87-0.97). Similar findings were associated with the FIB-4 greater than 2.67 threshold. These codes were associated with cirrhosis on local validation. A local validation cohort of patients with dementia showed a similar percentage of high FIB-4 scores (4.4%-11.2%).

Conclusions and Relevance

The findings of this cohort study suggest that clinicians encountering patients with dementia should be encouraged to screen for cirrhosis using the FIB-4 score to uncover reversible factors associated with cognitive impairment, such as HE, to enhance outcomes.

Identification of Novel, Replicable Genetic Risk Loci for Suicidal Thoughts and Behaviors Among US Military Veterans

Importance

Suicide is a leading cause of death; however, the molecular genetic basis of suicidal thoughts and behaviors (SITB) remains unknown.

Objective

To identify novel, replicable genomic risk loci for SITB.

Design, Setting, and Participants

This genome-wide association study included 633 778 US military veterans with and without SITB, as identified through electronic health records. GWAS was performed separately by ancestry, controlling for sex, age, and genetic substructure. Cross-ancestry risk loci were identified through meta-analysis. Study enrollment began in 2011 and is ongoing. Data were analyzed from November 2021 to August 2022.

Main Outcome and Measures

SITB.

Results

A total of 633 778 US military veterans were included in the analysis (57 152 [9%] female; 121 118 [19.1%] African ancestry, 8285 [1.3%] Asian ancestry, 452 767 [71.4%] European ancestry, and 51 608 [8.1%] Hispanic ancestry), including 121 211 individuals with SITB (19.1%). Meta-analysis identified more than 200 GWS (P < 5 × 10-8) cross-ancestry risk single-nucleotide variants for SITB concentrated in 7 regions on chromosomes 2, 6, 9, 11, 14, 16, and 18. Top single-nucleotide variants were largely intronic in nature; 5 were independently replicated in ISGC, including rs6557168 in ESR1, rs12808482 in DRD2, rs77641763 in EXD3, rs10671545 in DCC, and rs36006172 in TRAF3. Associations for FBXL19 and AC018880.2 were not replicated. Gene-based analyses implicated 24 additional GWS cross-ancestry risk genes, including FURIN, TSNARE1, and the NCAM1-TTC12-ANKK1-DRD2 gene cluster. Cross-ancestry enrichment analyses revealed significant enrichment for expression in brain and pituitary tissue, synapse and ubiquitination processes, amphetamine addiction, parathyroid hormone synthesis, axon guidance, and dopaminergic pathways. Seven other unique European ancestry-specific GWS loci were identified, 2 of which (POM121L2 and METTL15/LINC02758) were replicated. Two additional GWS ancestry-specific loci were identified within the African ancestry (PET112/GATB) and Hispanic ancestry (intergenic locus on chromosome 4) subsets, both of which were replicated. No GWS loci were identified within the Asian ancestry subset; however, significant enrichment was observed for axon guidance, cyclic adenosine monophosphate signaling, focal adhesion, glutamatergic synapse, and oxytocin signaling pathways across all ancestries. Within the European ancestry subset, genetic correlations (r > 0.75) were observed between the SITB phenotype and a suicide attempt-only phenotype, depression, and posttraumatic stress disorder. Additionally, polygenic risk score analyses revealed that the Million Veteran Program polygenic risk score had nominally significant main effects in 2 independent samples of veterans of European and African ancestry.

Conclusions and Relevance

The findings of this analysis may advance understanding of the molecular genetic basis of SITB and provide evidence for ESR1, DRD2, TRAF3, and DCC as cross-ancestry candidate risk genes. More work is needed to replicate these findings and to determine if and how these genes might impact clinical care.

Specific Challenges in Geriatric Cirrhosis and Hepatic Encephalopathy

As the world's population ages, diseases predominantly found in the elderly now overlap with diseases that were thought to be the purview of younger patients. This includes chronic liver disease, which affects more than 2 billion people worldwide. Owing to the obesity epidemic (and associated metabolic diseases), nonalcoholic fatty liver disease has become the most common cause of chronic liver disease and cirrhosis. A major complication of cirrhosis is hepatic encephalopathy (HE), which becomes challenging to diagnose in elderly patients. HE is usually included in the differential diagnosis of acute delirium but not of reversible dementias. To illustrate this point, we present 2 cases of older patients that were misdiagnosed as having dementia and Parkinson's disease or a parkinsonian syndrome but had contributions from cirrhosis. Both cognitive impairment and tremor resolved with treatment of HE.

Harmonizing Genetic Ancestry and Self-identified Race/Ethnicity in Genome-wide Association Studies

Large-scale multi-ethnic cohorts offer unprecedented opportunities to elucidate the genetic factors influencing complex traits related to health and disease among minority populations. At the same time, the genetic diversity in these cohorts presents new challenges for analysis and interpretation. We consider the utility of race and/or ethnicity categories in genome-wide association studies (GWASs) of multi-ethnic cohorts. We demonstrate that race/ethnicity information enhances the ability to understand population-specific genetic architecture. To address the practical issue that self-identified racial/ethnic information may be incomplete, we propose a machine learning algorithm that produces a surrogate variable, termed HARE. We use height as a model trait to demonstrate the utility of HARE and ethnicity-specific GWASs.

Male menopause

Menopause is the cessation of menses caused by the age-associated decline in gonadal hormone secretion in women. Although men do not menstruate, they do have an age-associated decline in gonadal hormone secretion. This "male menopause" is associated with loss of libido, loss of muscle mass and various other undesirable effects. The underlying causes of decreased testosterone production in older men may include decreased hypothalamic gonadotropin releasing hormone (GnRH) secretion, impaired feedforward effect of luteinizing hormone (LH) on testosterone secretion and decreased testosterone release from the Leydig cells. When chronic illness is superimposed on healthy aging, there are further decrements in testosterone availability. Although a consensus has not been reached, various studies suggest that older men may benefit from testosterone supplementation. For example, testosterone supplementation to older men seems to cause increased muscle protein synthesis, increased muscle strength and decreased cholesterol. Nevertheless, if testosterone supplementation is provided, clinicians must be vigilant to detect adverse effects such as accelerated growth of prostate carcinoma.

Disorders of male sexual function

Sexuality remains an important issue in the older population. In spite of a decreased ability to achieve an erection, there is continued sexual desire. Many studies suggest that erectile dysfunction in the aged is primarily caused by age-associated chronic disease rather than normal, healthy aging. Therefore, preventive measures that are aimed at the underlying diseases should be sought. Nevertheless, effective treatment options are now available to successfully regain sexual function and thereby, improve quality of life.

Unequal impact of short-term testosterone repletion on the somatotropic axis of young and older men

The present clinical study compares the impact of low- and high-dose parenteral testosterone (T) supplementation on daily GH secretory patterns and serum IGF-I, IGFBP-1, and IGFBP-3 concentrations in healthy older (60-82 yr) and young (20-40 yr) men. To this end, we administered three consecutive weekly injections of randomly ordered saline and either a low (100 mg) or a high (200 mg) dose of testosterone enanthate im; namely, saline (n = 17, young and n = 16, older), a low dose (n = 8 young, n = 8 older) and a high dose (n = 9 young, and n = 8 older) of androgen. To monitor somatotropic-axis responses, blood was sampled every 10 min for 24 h for later chemiluminescence-based assay of serum GH, RIA of serum IGF-I, and immunoradiometric assay of serum IGFBP-1 and IGFBP-3 concentrations. Data were analyzed via a nested analysis of covariance statistical design. At baseline (saline injection), older, compared with young, men maintained: 1) similar serum total T, IGFBP-1, and IGFBP-3 but reduced IGF-I concentrations, namely, mean (+/- SEM) IGF-I 160 plus or minus 15 vs. 280 plus or minus 18 microg/liter, (P < 0.001); 2) reduced GH secretory burst mass (0.68 +/- 0.09 vs. 1.2 +/- 0.20 microg/liter, P = 0.031); 3) more disorderly GH release patterns (approximate entropy 0.501 +/- 0.058 vs. 0.288 +/- 0.021, P < 0.001); and 4) blunted 24-h rhythmic GH output (nyctohemeral amplitude 0.25 +/- 0.05 vs. 0.47 +/- 0.08 microg/liter, P = 0.025). Serum T concentrations (ng/dl) did not differ in the two age groups supplemented with either a low dose [550 +/- 50 (young) and 544 +/- 128 (older)] and high [1320 +/- 92 (young) and 1570 +/- 140 (older)] dose of T. The 100-mg dose of androgen exerted no detectable effect on GH secretion in either age cohort but increased the serum IGF-I concentration in young men by 20% (P = 0.00098). The 200-mg dose of T failed to alter daily GH production in young volunteers but in older men stimulated: 1) a 2.03-fold rise in the mean (24-h) serum GH concentration (P = 0.0053, compared with the response to saline); 2) a 1.20-fold increase in basal (nonpulsatile) GH production (P = 0.039); 3) a 2.15-fold amplification of GH secretory burst mass (P = 0.0020); 4) a 2.17-fold elevation of the Mesor of nyctohemeral GH output (P = 0.025); 5) a 1.79-fold enhancement in GH approximate entropy (P = 0.0003); and 6) a 40% increase in the fasting serum IGF-I concentration (P = 0.000005). Multivariate statistical analysis indicated that following high-dose T administration, the E2 increment significantly predicted the IGF-I increment in both age groups combined (P = 0.003); T dose positively forecast the serum total IGF-I concentration (P = 0.0031); and age and T dose jointly determined serum LH concentrations (P = 0.031). In summary, neither a physiological nor a pharmacological dose of T administered parenterally for 3 wk augments daily GH secretion in eugonadal young men. In contrast, a high dose of aromatizable androgen significantly amplifies 24-h basal, pulsatile, entropic, and nyctohemerally rhythmic GH production and elevates the serum IGF-I concentration in older men. The mechanistic basis for the foregoing age-related distinction in GH/IGF-I axis responsivity to T is not known.

The gastrocolic trunk of Henle in pancreatic surgery: an anatomo-clinical study

From 37 peroperative and cadaver anatomical investigations, it was concluded that, in contrast to the information in common texts on anatomy and surgery, a venous gastrocolic trunk was observed in only 46% of subjects; a true bipod gastrocolic trunk of Henle was a rare (8%) phenomenon. In this respect, a variate venous anatomy at the inferior border of the neck of the pancreas, as observed in this study, must be taken into account during pancreatic surgery and radiological procedures in the pancreas.

Testosterone improves rehabilitation outcomes in ill older men

OBJECTIVES

To determine whether testosterone supplementation improves rehabilitation outcomes in ill older men.

DESIGN

A randomized, placebo-controlled, double-blind study.

SETTING

A Geriatric Evaluation and Management (GEM) unit based at a university- affiliated Veterans Affairs Medical Center.

PARTICIPANTS

Fifteen men aged 65 to 90 years admitted to the GEM for rehabilitation.

INTERVENTION

Subjects were randomized to receive weekly intramuscular injections with testosterone enanthate 100 mg or placebo.

MEASUREMENTS

Task-specific performance using the Functional Independence Measure (FIM) and grip strength was measured at the onset of the study and at the time of discharge from the GEM.

RESULTS

At baseline, FIM scores were similar between the placebo and the testosterone group (73.7 vs 70.7, P = .637), as was grip strength (49.7 vs 55.3 pounds, P = .555). At discharge from the GEM, testosterone-treated patients had improved FIM scores compared with baseline (93.6 vs 70.7; P = .012) and grip strength (68.7 vs 55.3 pounds; P = .033). In the placebo group there was no significant improvement of FIM scores compared with baseline (78.0 versus 73.7; P = .686) or of grip strength (48.9 vs 49.7 pounds; P = .686).

CONCLUSIONS

Testosterone supplementation may improve rehabilitation outcomes in ill older men.

Older men manifest multifold synchrony disruption of reproductive neurohormone outflow

Under a working clinical hypothesis that aging putatively disrupts neuroendocrine control mechanisms, here we test a specific corollary notion that transitions in sleep stage, oscillations in nocturnal penile tumescence (NPT; a neurogenically organized signal), and the rates of instantaneous secretion of LH and/or testosterone are jointly synchronous in healthy young, but not older, men. To this end, we evaluated 10 young (aged 21-31 yr) and 8 older (aged 65-74 yr) men by intensive overnight multisite monitoring, viz. simultaneous electro-encephalogram and NPT recordings (every 30 s) and remote blood sampling (every 2.5 min) to quantitate LH and testosterone release. Waveform-independent deconvolution and cross-correlation analyses of these neurohormone outflow measures revealed that healthy young men sustain four salient physiological linkages overnight: 1) a strong inverse (confirmatory) relationship between sleep stage and NPT activity, such that deeper sleep is accompanied by suppression of NPT; 2) consistent coupling between NPT and testosterone secretion, wherein heightened NPT activity respectively precedes and follows increased testosterone secretion by 12.5-32.5 and 50-60 min; 3) evident synchrony between sleep stage and testosterone secretion, in which testosterone secretion increases over a 30-min window (-2.5 to 25 min) while sleep deepens; and 4) a close temporal linkage between instantaneous LH release and NPT oscillations, whereby LH secretion increases 55-62.5 min before and again 5-30 min after NPT declines. In contrast, older men manifested global loss of expected young adult synchrony; namely, 1) abolition of the inverse relationship between sleep stage and NPT, 2) decorrelation of NPT oscillations and testosterone secretion, 3) decoupling of testosterone release and deep sleep, and 4) abrogation of the linkage between LH secretion and penile detumescence. In summary, high intensity overnight monitoring of multiple reproductive neuroendocrine outflow measures simultaneously in young men delineates prominent neurophysiological coupling among sleep transitions and NPT activity, LH and testosterone secretion or NPT oscillations, and testosterone secretion and deepening sleep stage. In contrast, healthy older men exhibit near-universal disruption of physiological young adult synchronicity. Thus, we conclude that male reproductive aging is marked by erosion of coordinate regulation among sleep transitions, central nervous system-directed NPT activity, and hypothalamically driven episodic GnRH/LH (and thereby Leydig cell testosterone) secretion. Whether analogous multifold uncoupling of neurohormone signals emerges in the course of reproductive aging in women or in nonhuman species is not yet known.

Synthetic somatostatin analog (octreotide) suppresses daytime growth hormone secretion equivalently in young and older men: preserved pituitary responsiveness to somatostatin's inhibition in aging

OBJECTIVE

To gain greater insight into the mechanisms controlling the low daytime rate of growth hormone (GH) secretion in older men.

DESIGN

We conducted a randomized, controlled study of GH secretion during inhibition by octreotide, a somatostatin analog.

PARTICIPANTS

Nine young (35-44 years) and ten older (62-79 years) healthy men participated.

INTERVENTION

Octreotide versus nothing, while subjects were on a standardized diet.

MEASUREMENTS

All subjects were assessed on two separate occasions: baseline and at time of the intervention of octreotide (100 microg subcutaneously); the order of the intervention was randomly assigned. Octreotide was administered at 8:00 a.m. Venous sampling was performed every 10 minutes for 8 hours (8:30 a.m. to 4:30 p.m.). To estimate the joint parameters of pulsatile and basal (between secretory pulses) GH secretion, we used an ultrasensitive chemiluminescence-based GH assay and multiparameter deconvolution analysis.

RESULTS

Compared with baseline, octreotide markedly reduced mean (8-hour) serum GH concentrations in both young (0.585+/-0.255 microg/L vs 0.070+/-0.029 microg/L; P = .008) and older (0.397+/-0.107 microg/L vs 0.087+/-0.027 microg/L; P = 0.005) men. In younger men, octreotide decreased the serum GH concentration primarily by suppressing the mass of GH released per secretory pulse (2.4+/-0.9 microg/L vs 1.0+/-.7 microg/L; P = .015) and the interpulse (basal) rate of GH release (0.0014+/-0.0003 microg/L/min vs 0.0006+/-0.0002 microg/L/min; P = .051). In older men, octreotide also restrained the mass of GH per secretory pulse (1.5+/-0.4 microg/L vs 0.4+/-0.1 microg/L; P = .028) and lowered basal GH release (0.0014+/-0.0003 microg/L/min vs 0.0004+/-0.0001 microg/L/min; P = .007). There were no significant differences when the older men were compared with the young controls.

CONCLUSIONS

Our data suggest that the daytime relative GH deficiency seen in older men is not a result of excessive pituitary susceptibility to the inhibitory capabilities of somatostatin, but more likely reflects impoverished endogenous GHRH drive and/or heightened release of brain somatostatin.

Changes in the compound action current amplitudes in relation to the conduction velocity and functional recovery in the reconstructed peripheral nerve

The average axon diameter in the proximal segment of a transected and reconstructed peripheral nerve will decrease shortly after the transection and increase again when the regenerating axons make contact with their targets. The magnetically recorded nerve compound action current (NCAC) amplitude and the conduction velocity (CV) are directly related to the axon diameters. In this experiment, the peroneal nerve was unilaterally transected and reconstructed in 42 rabbits. After 3, 4.5, 6, 8, 12, 20, and 36 weeks of regeneration time, hind leg motor function recovery, NCAC amplitude, and CV(1st peak) were studied. Our results demonstrate a significant decrease in signal amplitude and CV in the first 8 weeks after reconstruction. These decreases are related (P < 0.05). After 8 weeks of regeneration time, motor function and the CV of the recorded signals start to recover, but the signal amplitudes do not. Based on the correlation of the CV and signal amplitude with axon diameter, they would both be expected to increase with recovering function. As an explanation for this lack of increase of signal amplitude, we suggest that, at the same time as some axons reach their target organs and start to mature, a number of the axons which have not reached a proper target organ will lose their signal-conducting capability. This will cause a decrease in compound signal amplitude, which cancels out the expected increase in NCAC amplitude, due to axonal maturation.

A magnetic evaluation of peripheral nerve regeneration: I. The discrepancy between magnetic and histologic data from the proximal segment

Histologic techniques can quantify the number of axons in a nerve, but give no information about electrical conductibility. The number of functional myelinated neuronal units in a nerve can be quantified based on a magnetic recording technique. When studying reconstructed peripheral nerves a significant difference between the results found with these two techniques can be observed. A comparison was made between the long-term changes in the number of histologically and magnetoneurophysiologically measured neuronal units proximal to a nerve reconstruction. This study was performed on 6 New Zealand White rabbits, 20 weeks after the peroneal nerve had been reconstructed. The contralateral nerves were used as a control. Histologic examination demonstrates a statistically significant decrease of approximately 5% in the number of myelinated fibers. The magnetoneurophysiological results demonstrate a decrease which is estimated to be caused by the loss of approximately 50% of the functional myelinated neuronal units in the nerve. Therefore we conclude that of the initially available myelinated neuronal units, 5% degenerate completely, 45% are vital but lose their signal conducting capability, and the remaining 50% are vital and continue to conduct signals. Apparently, only this latter group of 50% of the initially available functional neuronal units appears to remain available for functional recovery.

A magnetic evaluation of peripheral nerve regeneration: II. The signal amplitude in the distal segment in relation to functional recovery

Motor and sensory function in a healthy nerve is strongly related to the number of neuronal units connecting to the distal target organs. In the regenerating nerve the amplitudes of magnetically recorded nerve compound action currents (NCACs) seem to relate to the number of functional neuronal units with larger diameters regenerating across the lesion. The goal of this experiment was to compare the signal amplitudes recorded from the distal segment of a reconstructed nerve to functional recovery. To this end, the peroneal nerves of 30 rabbits were unilaterally transected and reconstructed. After 6, 8, 12, 20, and 36 weeks of regeneration time the functional recovery was studied based on the toe-spread test, and the nerve regeneration based on the magnetically recorded NCACs. The results demonstrate that the signal amplitudes recorded magnetically from the reconstructed nerves increase in the first 12 weeks from 0% to 21% of the amplitudes recorded from the control nerves and from 21% to 25% in the following 23 weeks. The functional recovery increases from absent to good between the 8th and the 20th week after the reconstruction. A statistically significant relation was demonstrated between the signal amplitude and the functional recovery (P < 0.001). It is concluded that the magnetic recording technique can be used to evaluate the quality of a peripheral nerve reconstruction and seems to be able to predict, shortly after the reconstruction, the eventual functional recovery.

Older males secrete luteinizing hormone and testosterone more irregularly, and jointly more asynchronously, than younger males

New statistical perspectives on the secretory patterns of both luteinizing hormone (LH) and testosterone (T) may prove useful in further understanding the aging process, and possibly ultimately in improving the diagnosis and treatment of spermatogenetic failure and loss of sexual interest. We examined serum concentration time-series for LH and T in 14 young (21-34 years of age) and 11 aged (62-74 years of age) healthy men. For each subject, blood samples were obtained at 2.5-min intervals during a sleep period, with an average sampling duration of 7 hr. For each of LH and T, we used the model-independent statistic approximate entropy (ApEn) to quantify the irregularity of the serum concentration time-series; to quantify joint LH-T secretory asynchrony, we employed the recently introduced cross-ApEn. Although mean (and SD) LH and T concentrations were indistinguishable in the two age groups (P > 0.25), for LH, aged subjects had greater ApEn values (1.525 +/- 0.221) than younger individuals (1.207 +/- 0.252), P < 0.003, indicating more irregular secretion in the older cohort. For T, aged subjects also had greater ApEn values (1.622 +/- 0.120) than younger counterparts (1.384 +/- 0.228), P < 0.004. In young, but not older men, ApEn(T) significantly exceeded ApEn(LH), P < 0.02. Aged subjects had greater cross-ApEn values (1.961 +/- 0.121) than younger subjects (1.574 +/- 0.249), P < 10(-4), with nearly 100% sensitivity and specificity, indicating greater LH-T asynchrony in the older group. In conjunction with previous findings of greater irregularity of growth hormone release with increasing age, we propose that increased secretory irregularity with advancing age may be a widespread hormonal phenomenon. Finally, theoretically, we clarify the need for quantifications such as ApEn and cross-ApEn via a study of a "variable lag" pulsatile process, and empirically note the potential wide applicability of cross-ApEn to quantify asynchrony in interconnected (hormonal) networks.

Alkalization does not alleviate penile pain induced by intracavernous injection of prostaglandin E1

PURPOSE

A prospective, randomized, double-blind study was done to determine whether alkalization of prostaglandin E1 decreases pain associated with intracavernous injection.

MATERIALS AND METHODS

Ten subjects with a history of pain following at least 70% of injections of prostaglandin E1 received 2 injections of prostaglandin E1, 1 with and 1 without sodium bicarbonate. Patients reported the duration and intensity of pain following each injection.

RESULTS

Comparing injections of prostaglandin E1 with and without bicarbonate, there were no significant differences in number of subjects reporting pain, or duration and intensity of pain.

CONCLUSIONS

Addition of sodium bicarbonate does not alleviate penile pain associated with injection of prostaglandin E1.

Quality of life in patients using self-administered intracavernous injections of prostaglandin E1 for erectile dysfunction

PURPOSE

We assessed changes in quality of life after 6 months of self-injections of prostaglandin E1 for the treatment of erectile dysfunction.

MATERIALS AND METHODS

A prospective study was done at a university affiliated Veterans Affairs medical center of patients using prostaglandin E1 at home. Quality of life was assessed with the Case Western Reserve University sexual functioning questionnaire and the Duke health profile. These questionnaires were administered before initiation and after 6 months of prostaglandin E1 therapy.

RESULTS

Of 16 subjects injecting prostaglandin E1 at home 15 completed 6 months of therapy, and 13 of them completed both questionnaires. While using prostaglandin E1 we found an increase in the frequency of sexual activity from 2.9 to 5.5 times during the prior month (p = 0.01), rigidity of erection scores from 3.8 to 7.6 (p = 0.002, score 0-no erection to 8-full erection) and sexual satisfaction scores from 2.5 to 4.1 (p = 0.03, score 0-extremely unsatisfied to 5-extremely satisfied). We also found improvements in mental health scores from 80.0 to 92.3 (p = 0.007), social health scores from 61.5 to 80.8 (p = 0.004) and self-esteem scores from 72.3 to 86.9 (p = 0.01) on a scale of 0 to 100, where a higher score indicates better health.

CONCLUSIONS

Self-injection of prostaglandin E1 improves sexual satisfaction and quality of life in men with erectile dysfunction.

Slow injection of prostaglandin E1 decreases associated penile pain

OBJECTIVES

A randomized, double-blind study to determine whether speed of intracavernous injection of prostaglandin E1 (PGE1) is associated with pain.

METHODS

On two separate occasions, using two different speeds of injection (5 versus 60 seconds), 11 subjects received the same dose of PGE1 that they used at home. The presence, duration, and intensity of pain were recorded.

RESULTS

We found that fast penile injection of PGE1 was associated with a greater intensity of pain (P = 0.04).

CONCLUSIONS

Slow injection of PGE1 is less often associated with penile pain, the most common adverse effect of this treatment.

Long-term efficacy of a new formulation of prostaglandin E1 as treatment for erectile failure

PURPOSE

We determined the long-term efficacy of intracavernous injection of a new formulation of prostaglandin E1 (Caverject) as treatment for erectile failure.

MATERIALS AND METHODS

A prospective study was done at a university affiliated Veterans Affairs medical center. Subjects with erectile failure received injections of prostaglandin E1 at the office and self-administered injections at home for up to 18 months.

RESULTS

Of 16 patients who performed home injections 15 completed 6 months and 10 completed 18 months of therapy. Patient and spousal satisfaction with intercourse was 90% for months 1 to 6, and patient satisfaction was 95% for months 7 to 18.

CONCLUSIONS

Prostaglandin E1 was highly effective at producing penile rigidity and an erection with satisfactory vaginal intercourse.

Amplified nocturnal luteinizing hormone (LH) secretory burst frequency with selective attenuation of pulsatile (but not basal) testosterone secretion in healthy aged men: possible Leydig cell desensitization to endogenous LH signaling--a clinical research center study

The specific mechanisms underlying the relative hypogonadism of aging remain to be elucidated fully. We used frequent venous sampling (every 2.5 min), sensitive and specific LH and testosterone assays, and deconvolution analysis of the endocrine time series to delineate the differences between healthy young (n = 10, age 21-34 yr) and aged (n = 8, age 62-74 yr) men in the nocturnal secretion of LH and testosterone and their half-lives. We found that elderly men vs. young men had more frequent bursts of LH secretion (1.4 vs. 0.9/h, P = 0.003), less testosterone secreted per testosterone secretory burst (9.2 vs. 17.0 nmol/L, P = 0.021), and less testosterone secreted per hour (10.7 vs. 25.0 nmol/L.h, P = 0.05). As the frequency of nocturnal LH secretory bursts increased, the frequency of testosterone bursts decreased (r = -0.746, P = 0.034). We conclude that healthy aging is associated with diminished nocturnal testosterone production attributable to 1) a decrement in the mass of testosterone released per burst and 2) an inadequate response by the pituitary gland to enhance testosterone production via an accelerated LH secretory pulse frequency. We speculate that this may reflect a partial desensitization of Leydig cells to LH.

Somatotopy of monkey premotor cortex examined with microstimulation

We reinvestigated the organization of the premotor cortex (PM) using intracortical microstimulation. Movements of forelimb, hindlimb, and orofacial structures were evoked from broad regions of PM that appeared to be contiguous with other motor areas. There were two principal findings: (1) the somatotopy of PM lies roughly parallel to that of the primary motor cortex (MI). Forelimb movements were evoked from sites deep in the caudal bank of the arcuate sulcus and throughout the adjacent cortex bounded by a face representation (laterally) and a hindlimb representation (medially and caudally); (2) unlike the MI, the PM forelimb representation overlaps significantly with its own face representation. PM hindlimb movement sites overlap only slightly with PM forelimb sites, in a manner similar to the MI. There was no obvious boundary between PM, MI, or supplementary motor area hindlimb representations. The present findings are discussed in relation to recently identified subdivisions of the PM.

Loss of viable neuronal units in the proximal stump as possible cause for poor function recovery following nerve reconstructions

Function recovery after nerve reconstructions is often poor. Could this be caused by a loss of viable neuronal units proximal to the nerve reconstruction? The number of neuronal units (i.e., a motor or sensory neuron, including its axon and axonal branches) in the proximal segments of reconstructed peripheral nerves were studied using a novel magnetic recording technique. In five rabbits a common personal nerve was transected and microsurgically reconstructed. After 8 weeks regeneration time the nerve compound action signals were recorded magnetically from the reconstructed as well as from the healthy contralateral peroneal nerve and from peroneal nerves of five unoperated control animals. The amplitudes of the recorded signals were compared and the diameter distribution histograms were calculated. These calculations were based on the conduction distance between the stimulator and the sensor and the conduction velocities of 30 different axon diameter classes ranging from 3 to 18 microns. Our results indicate that there is a reduction of approximately 50% in the number of viable neuronal units at 10 mm proximal to a simple nerve reconstruction after 8 weeks regeneration time. The number of neuronal units innervating a hand is strongly correlated with clinical function in a healthy hand. The reduction in viable neuronal units after a reconstruction, demonstrated in our experiments, corresponds with a frequently clinically observed decrease in function after nerve reconstructions. Therefore, we suggest that the number of viable neuronal units may be a good indicator of final functional recovery.

The lowest effective dose of prostaglandin E1 as treatment for erectile dysfunction

The recommended dose of prostaglandin E1 as treatment for erectile dysfunction has been reported to be 10 to 40 micrograms. However, adverse effects probably increase with increasing doses. We conducted a prospective, single-blind, dose-escalating study of prostaglandin E1 on 20 men with erectile dysfunction of various etiologies. The response to prostaglandin E1 was assessed by penile palpation and RigiScan rigidity monitoring. A total of 17 patients completed the study: 1 achieved rigidity with 1 microgram., 2 with 2 micrograms. and 4 with 3 micrograms. prostaglandin E1, while more than 70% achieved rigidity with 5 micrograms. or less and more than 80% had a full erection with 20 micrograms. Of 138 injections there were 2 episodes of pain after injection. We conclude that the often recommended starting dose of 20 micrograms. is too high. A more appropriate starting dose is 2.5 micrograms. with increments of 2.5 micrograms. until the lowest effective dose is achieved. This approach may lessen the major impediments to prostaglandin E1 use, that is burning and pain.

Topography of saccadic eye movements evoked by microstimulation in rabbit cerebellar vermis

1. We investigated saccadic eye movements elicited by microstimulation in the vermis of the rabbit. Scleral search coils were implanted under the conjunctiva of both eyes and a recording chamber was placed over the cerebellar vermis. 2. Conjugate saccadic eye movements were evoked in lobules VIa, b and c and VII of the vermis by currents ranging from 4 to 60 microA. All movements were horizontal with no apparent vertical component. 3. The cortex on both sides of the vermal mid-line could be divided in two zones, dependent on the direction of elicited saccades. In the medial zone saccades were directed ipsilaterally, in the lateral zone contralaterally. 4. We conclude that the topography of saccadic eye movements in the rabbit cerebellar vermis is, unlike in monkey and cat, organized in parasagittal zones.

Peyronie's-like plaque after penile injection of prostaglandin E1

Intracavernous injection of vasoactive medication may cause fibrosis of the tunica albuginea or corpus cavernosum. These adverse effects have been clearly linked to papaverine and phentolamine but to our knowledge the development of fibrosis or a Peyronie's-like plaque after the injection of prostaglandin E1 has not been previously described. We report a case of intracavernous hematoma, penile curvature deformity and Peyronie's-like plaque that developed after initiating intracorporeal self-injection of prostaglandin E1 for erectile dysfunction.

A comparison of electric and magnetic compound action signals as quantitative assays of peripheral nerve regeneration

The evaluation of peripheral nerve regeneration is of great interest in clinical as well as in experimental situations. However, there are few techniques that give early and quantitative information on the status of the regeneration process. If quantitative assays would be available, different surgical techniques and medications could be evaluated more accurately in relation to axonal ingrowth and functional recovery. The purpose of this study was to investigate the merits of nerve compound action signals (NCASs) recorded electrically and signals recorded with a novel magnetic recording technique. We compared the two techniques in the rabbit peroneal nerve, 2, 4, 6, and 8 weeks after a nerve reconstruction. Our conclusions are that the signals recorded with the magnetic sensor are far more reproducible and less prone to stimulus artifact than the electrically recorded signals. Furthermore, the magnetic recording shows that the number of axons that have regenerated increases with time. Previously, this could only be determined with histological studies. Other ingrowth parameters that can be quantified are the average ingrowth distance, and the variation between axons in ingrowth velocity.

Replantation of the radial side of the hand in the rhesus monkey: anatomical and functional aspects. A preliminary study to composite tissue allografting

Before human hand transplantation can even be considered, an appropriate research model must be studied in a non-human primate. The first ray of the hand, augmented with a radial forearm flap, was chosen as a functional composite tissue graft. Four technically successful replantation of the radial unit have been carried out. One monkey died on the first post-operative day due to cardiac arrythmia. Normal wound healing occurred in the other three animals. In three monkeys, functional sensory and motor recovery was almost complete. The monkeys were able to pick up small particles of food with the index finger and thumb. It is suggested that this model could be used for allogeneic composite tissue transplantation in a non-human primate.

Glucocorticoids decrease vitamin D receptor number and gene expression in human osteosarcoma cells

The mechanisms by which glucocorticoids (GC) inhibit some actions of vitamin D [1,25-(OH)2D3] are not well understood, but there is growing evidence that GC alter vitamin D receptor (VDR) number. We studied the effects of dexamethasone (DEX) on VDR number and mRNA in the human osteosarcoma cell line, MG-63. The effects of DEX on 1,25-(OH)2D3 binding were examined by incubating confluent cells overnight in media without or with 10(-6) M DEX. DEX decreased VDR number (B max) by approximately 70% (110 versus 32 fmol/mg cellular protein, p less than 0.001) without significantly changing the apparent affinity (K'D) of 1,25-(OH)2D3 for its receptor (3.8 versus 2.2 x 10(-10) M, p greater than 0.05). Overnight incubation of MG-63 cells with DEX produced a time- and dose-responsive decrease in VDR mRNA compared to untreated controls (p less than 0.01). To determine the mechanism of the DEX-mediated decrease in VDR mRNA, the effect of DEX on VDR mRNA stability was studied. We found that the half-life for the VDR mRNA was approximately 5.7 h and was not significantly changed when the cells were incubated with DEX (approximately 6.3 h). We conclude that DEX decreases both VDR number and mRNA in MG-63 osteosarcoma cells. Since the half-life of VDR mRNA was not significantly modified by dexamethasone, glucocorticoids appear to decrease VDR mRNA by inhibiting VDR gene transcription or by affecting the processing of VDR mRNA.

Learning-dependent neuronal activity in the premotor cortex: activity during the acquisition of conditional motor associations

It has been proposed that the premotor cortex plays a role in the selection of motor programs based on environmental context. To test this hypothesis, we recorded the activity of single neurons as monkeys learned visuomotor associations. The hypothesis predicts that task-related premotor cortical activity before learning should differ from that afterward. We found that a substantial population of premotor cortex neurons, over half of those adequately tested, showed the predicted learning-dependent changes in activity. The present findings support a role for premotor cortex in motor preparation, generally, and suggest a specific role in the selection of movements on the basis of arbitrary associations.

Eye-movement representation in the frontal lobe of rhesus monkeys

We systematically explored the frontal eye field (FEF), the supplementary eye field (SEF), and nearby regions of the frontal cortex to establish the limits of these or possible adjacent eye-movement fields in macaque monkeys. We found a medio-laterally oriented band of saccadic eye-movement sites that extended from the inferior limb of the arcuate sulcus onto the medial surface of the hemisphere and into the dorsal bank of the cingulate sulcus. Two parts of this region may be outside previously described eye-movement areas. We conclude that eye movements are more broadly represented in the frontal lobes than previously described: either the SEF extends into the dorsal bank of the cingulate sulcus and laterally to the arcuate sulcus, or there are more than two frontal eye-movement fields.

Preparation of visually cued arm movements in monkey. Involvement of inferior parietal cortex

Single-unit activity was recorded in monkey inferior parietal lobule (IPL) during performance of a visually cued limb motor task. Many neurons in the IPL modulated their activity just after the visual cue was presented, similar to the neuronal activity observed in the premotor cortex in a previous experiment. It is suggested that IPL neurons are involved in preparation of visually cued limb movement. The present results are discussed in view of a possible role for IPL and premotor cortex in processing visual information for use by the primary motor area.

The involvement of monkey premotor cortex neurones in preparation of visually cued arm movements

Some neurones in macaque postarcuate premotor area modulate their firing frequency in relation to motor tasks which require visual information. We previously reported that a large proportion of these neurones modulate during execution of a detour reaching task in which the movement phase was separated in time from the phase in which the monkey received a visual cue for the movement required to retrieve a food reward. A large proportion of task-related neurones (75%) modulated during this 'visual' phase, in which no task-related movements were made. This modulation was related to the position of the food reward, which served as the visual cue. Most of these neurones were located in cortical area 6, close to the arcuate curvature and its spur, but also more caudally in area 4 and rostrally in area 8. In the present chronic recording experiments in monkeys, several variations of the original task were used in order to test whether the 'visual'-related neuronal modulation could be involved in preparation of the upcoming movement. This modulation is unlikely to be related to any eye or arm movements occurring during the visual phase or to changes in environmental illumination. Neither can it be related to the presence of the visual cue in a particular part of the visual field, since the pattern of neuronal modulation was similar when a cue with a fixed position was used. This modulation was, however, contingent upon the occurrence of food retrieval during the subsequent 'movement phase', since it was abolished or diminished during presentation of a 'food-reward' which the monkey did not retrieve. For several neurones, modulation pattern during the visual phase depended on whether the food reward was to be retrieved with a gross hand movement or with relatively independent finger movements. It is likely, therefore, that neurones in the postarcuate premotor cortex are involved in preparation for arm movements with the help of visual cues. The results are discussed in view of corticocortical pathways which might be involved in transmission of visual information from visual areas through parietal association areas and premotor cortex to the primary motor cortex.

Cortical afferents and efferents of monkey postarcuate area: an anatomical and electrophysiological study

A study has been made of the corticocortical efferent and afferent connections of the posterior bank of the arcuate sulcus in the macaque monkey. The distribution of efferent projections to the primary motor cortex (MI) was studied by injecting three different fluorescent retrograde tracers into separate regions of MI. The resultant labeling showed a discrete and topographically organized projection: neurons lying below the inferior limb of the arcuate sulcus project into the MI face area, while neurons located in the posterior bank of the inferior limb of the arcuate sulcus and in the arcuate spur region project into the MI hand area. These findings were confirmed electrophysiologically by demonstrating that postarcuate neurons could only be activated antidromically by stimulation within restricted regions of MI. HRP injections within postarcuate cortex indicated that afferents to this region arise from a number of cortical areas. However, the largest numbers of labeled neurons were found in the posterior parietal cortex (area 7b; PF) and in the secondary somatosensory region (SII). Neurons in both 7b (PF) and SII could be antidromically activated by postarcuate stimulation. It was further shown that stimulation of area 7b (PF) gives rise to short-latency synaptic responses in postarcuate neurons, including some neurons with identified projections to MI. The results are discussed in relation to the possible function of the postarcuate region of the premotor cortex in the sensory guidance of movement.

Behaviour of neurons in monkey peri-arcuate and precentral cortex before and during visually guided arm and hand movements

Neuron activity was recorded in monkey cerebral cortex during a visually guided reaching task. Cells located in the banks of the arcuate sulcus at its curvature changed their activity during the period in which the monkey saw a food reward in a certain position, but before it moved to retrieve the reward. A role of these neurons in visual guidance of arm and hand movements is postulated.

The role of dopaminergic systems in gamma-hydroxybutyrate-induced electrocorticogram hypersynchronization in the rat

The effects of dopaminergic agonists and antagonists on the duration of hypersynchronization induced in the electrocorticogram (ecog) by gamma-hydroxybutyrate (gamma-HB) were tested in rats. Apomorphine (0-2-8 mg kg-1), piribedil (2-5-10 mg kt-1) and haloperidol (0-5-1 mg kg-1) had no influence on the duration of the hypersynchrony. Amphetamine (1-5-6 mg kg-1) inhibited the hypersynchrony, while (3,4-dihydroxyphenylamino)-2-imidazoline (DPI; 5, but not 1, mg kg-1) prolonged its duration. The lack of effect of the dopamine receptor agonists apomorphine and piribedil, and the dopamine receptor blocker haloperidol, on the gamma-HB-induced hypersynchrony might indicate that the inhibition of the impulse flow in the nigrostriatal dopamine system by gamma-HB is not involved in the generation of the hypersynchrony. DPI is thought to be an agonist at a dopamine receptor not sensitive to apomorphine, and its facilitatory effect on gamam-HB-hypersynchrony can be interpreted in terms of a possible involvement of another dopamine system in the ecog hypersynchrony induced by gamma-HB. The antagonism of gamma-HB by amphetamine is possibly due to an indirect stimulatory effect on noradrenergic receptors.

Slow wave sleep and a state resembling absence epilepsy induced in the rat by gamma-hydroxybutyrate

The effect of gamma-hydroxybutyrate (GHB) in relatively low doses (12.5--200 mg/kg) on sleep stages, electrocorticogram (ECoG) patterns and behavior was investigated in the rat. 50-100 mg/kg GHB induced slow wave sleep but, in contrast to the cat, not paradoxical sleep. 200 mg/kg induced a hypersynchronous, bilaterally symmetrical ECoG pattern, which was different in amplitude and frequency distribution from normally occurring high amplitude patterns. When the hypersynchrony occurred in bursts, the rats displayed a sudden arrest of motor behavior. Convulsions were not induced. The results, together with the finding of others that GHB is a natural constituent of mammalian brain and our previous observation that the GHB-induced hypersynchrony can be antagonized by anti-absence (anti-petit mal) drugs are discussed in view of the possibility that GHB might play a role in the etiology of absence epilepsy in man.

Effect of clozapine on the sleep pattern in the rat

The effect of clozapine on the sleep pattern in the rat was studied after a single injection (2.5--20 mg/kg) and after daily administration for 11 consecutive days (2 X 20 mg/kg/day). After a single injection clozapine significantly suppressed REM sleep in a dose-related way, leaving slow wave sleep (SWS) unchanged. Follwing chronic administration, however, clozapine exerted its most prominent effect on SWS, the enhancement of which persisted for at least 3 days after discontinuation of treatment. REM sleep decreased with the development of tolerance and in the absence of rebound phenomena. The results are discussed in the light of disturbances in brain monoamines and the tolerance these amines developed to repeated administration of clozapine.

The drinking response of the chicken to peripheral and central administration of angiotensin II

Intravenous injection of Ang II (val5 angiotensin II amide) elicited an immediate drinking response in the domestic fowl which lasted at least 20 minutes. The minimal dosage needed was 300 mug. Intracranial injection of 10 mug Ang II through cannulas implanted in the anterior diencephalon caused a significant increase in water intake. The minimal intracranial dosage of Ang II which evoked drinking was 2.5 mug. Intracranial injection of isotonic KCl inhibited the drinking response induced by intravenously injected Ang II when administered simultaneously. This suggests that drinking caused by both intravenous or intracranial injection of Ang II is activated through identical brain regions. The positive drinking response of the chicken is repeated concecutive intracranial injections of Ang II declined from the first injection through the following ones.