Comparison of coronavirus disease 2019 (COVID-19) symptoms at diagnosis among healthcare personnel before and after the emergence of the omicron variant

We used a self-reporting system to compare symptom frequency of hospital personnel with coronavirus disease 2019 before and after the emergence of the Omicron variant. Omicron was more likely to result in asymptomatic carriage (7% vs 12%; P = .009), and fewer symptoms were observed in those with booster vaccination.

Effectiveness of MRNA booster vaccine among healthcare workers in New York City during the Omicron surge, December 2021 to January 2022

OBJECTIVE

To describe effectiveness of mRNA vaccines by comparing 2-dose (2D) and 3-dose (3D) healthcare worker (HCW) recipients in the setting of Omicron variant dominance. Performance of 2D and 3D vaccine series against SARS-CoV-2 variants and the clinical outcomes of HCWs may inform return-to-work guidance.

METHODS

In a retrospective study from December 15, 2020 to January 15, 2022, SARS-CoV-2 infections among HCWs at a large tertiary cancer centre in New York City were examined to estimate infection rates (aggregated positive tests / person-days) and 95% CIs over the Omicron period in 3D and 2D mRNA vaccinated HCWs and were compared using rate ratios. We described the clinical features of post-vaccine infections and impact of prior (pre-Omicron) COVID infection on vaccine effectiveness.

RESULTS

Among the 20857 HCWs in our cohort, 20,660 completed the 2D series with an mRNA vaccine during our study period and 12461 had received a third dose by January 15, 2022. The infection rate ratio for 3D versus 2D vaccinated HCWs was 0.667 (95% CI 0.623, 0.713) for an estimated 3D vaccine effectiveness of 33.3% compared to two doses only during the Omicron dominant period from December 15, 2021 to January 15, 2022. Breakthrough Omicron infections after 3D + 14 days occurred in 1,315 HCWs. Omicron infections were mild, with 16% of 3D and 11% 2D HCWs being asymptomatic.

DISCUSSION

Study demonstrates improved vaccine-derived protection against COVID-19 infection in 3D versus 2D mRNA vaccinees during the Omicron surge. The advantage of 3D vaccination was maintained irrespective of prior COVID-19 infection status.

Clinical and Genomic Characterization of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS CoV-2) Infections in mRNA Vaccinated Health Care Personnel in New York City

BACKGROUND

Vaccine-induced clinical protection against severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) variants is an evolving target. There are limited genomic level data on SARS CoV-2 breakthrough infections and vaccine effectiveness (VE) since the global spread of the B.1.617.2 (Delta) variant.

METHODS

In a retrospective study from 1 November 2020 to 31 August 2021, divided as pre-Delta and Delta-dominant periods, laboratory-confirmed SARS CoV-2 infections among healthcare personnel (HCP) at a large tertiary cancer center in New York City were examined to compare the weekly infection rate-ratio in vaccinated, partially vaccinated, and unvaccinated HCP. We describe the clinical and genomic epidemiologic features of post-vaccine infections to assess for selection of variants of concern (VOC)/variants of interest (VOI) in the early post-vaccine period and impact of B.1.617.2 (Delta) variant domination on VE.

RESULTS

Among 13658 HCP in our cohort, 12379 received at least 1 dose of a messenger RNA (mRNA) vaccine. In the pre-Delta period overall VE was 94.5%. Whole genome sequencing (WGS) of 369 isolates in the pre-Delta period did not reveal a clade bias for VOC/VOI specific to post-vaccine infections. VE in the Delta dominant phase was 75.6%. No hospitalizations occurred among vaccinated HCP in the entire study period, compared to 17 hospitalizations and 1 death among unvaccinated HCP.

CONCLUSIONS

Findings show high VE among HCP in New York City in the pre-Delta phase, with moderate decline in VE post-Delta emergence. SARS CoV-2 clades were similarly distributed among vaccinated and unvaccinated infected HCP without apparent clustering during the pre-Delta period of diverse clade circulation. Strong vaccine protection against hospitalization was maintained through the entire study period.

Risk of Healthcare-Associated Transmission of SARS-CoV-2 in Hospitalized Cancer Patients

Background

There is limited information on the risk of hospital-acquired coronavirus disease 2019 (COVID-19) among high-risk hospitalized patients after exposure to an infected patient or healthcare worker (HCW) in a nonoutbreak setting.

Methods

This study was conducted at a tertiary care cancer center in New York City from 10 March 2020 until 28 February 2021. In early April 2020, the study institution implemented universal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing at admission and retesting every 3 days through the hospital stay. Contact tracing records were reviewed for all exposures to SARS-CoV-2 positive patients and HCWs.

Results

From 10 March 2020 to 28 February 2021, 11 348 unique patients who were SARS-CoV-2 polymerase chain reaction (PCR) negative at the time of admission underwent 31 662 postadmission tests during their hospitalization, and 112 tested positive (0.98%). Among these, 49 patients housed in semiprivate rooms during admission resulted in 74 close contacts and 14 secondary infections within 14 days, for an overall attack rate of 18.9%. Among those exposed to a roommate undergoing an aerosol-generating procedure (AGP), the attack rate was 35.7%. Whole genome sequencing (WGS) corroborated transmission in 6/8 evaluated pairs. In addition, three transmission events occurred in 214 patients with significant exposure to 105 COVID-19 positive healthcare workers (1.4%).

Conclusions

The overall risk of hospital-acquired COVID-19 is low for hospitalized cancer patients, even during periods of high community prevalence. However, shared occupancy with an unrecognized case is associated with a high secondary attack rate in exposed roommates.

Lower Rate of Seropositivity to Measles Among Young Healthcare Personnel in New York City

We examined the prevalence of measles antibody among 12 349 newly hired HCP between 2009 and 2019. Younger HCP were significantly more likely to have no immunity. Compared with a 92.2% seropositive rate among 1057 persons hired at age >50 years, only 84.4% of approximately 10 000 HCP aged <40 years had protective antibody.

Determinants of COVID-19 disease severity in patients with cancer

As of 10 April 2020, New York State had 180,458 cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and 9,385 reported deaths. Patients with cancer comprised 8.4% of deceased individuals¹. Population-based studies from China and Italy suggested a higher coronavirus disease 2019 (COVID-19) death rate in patients with cancer^2,3, although there is a knowledge gap as to which aspects of cancer and its treatment confer risk of severe COVID-19⁴. This information is critical to balance the competing safety considerations of reducing SARS-CoV-2 exposure and cancer treatment continuation. From 10 March to 7 April 2020, 423 cases of symptomatic COVID-19 were diagnosed at Memorial Sloan Kettering Cancer Center (from a total of 2,035 patients with cancer tested). Of these, 40% were hospitalized for COVID-19, 20% developed severe respiratory illness (including 9% who required mechanical ventilation) and 12% died within 30 d. Age older than 65 years and treatment with immune checkpoint inhibitors (ICIs) were predictors for hospitalization and severe disease, whereas receipt of chemotherapy and major surgery were not. Overall, COVID-19 in patients with cancer is marked by substantial rates of hospitalization and severe outcomes. The association observed between ICI and COVID-19 outcomes in our study will need further interrogation in tumor-specific cohorts.

Atypical presentation of Legionella pneumonia among patients with underlying cancer: A fifteen-year review

BACKGROUND

Immunocompromised patients, especially those receiving treatment with corticosteroids and cytotoxic chemotherapy are at increased risk for developing Legionella pneumonia.

OBJECTIVE

The aim of this study was to determine clinical and radiographic characteristics of pulmonary infection due to Legionella in persons undergoing treatment for cancer and stem cell transplant (SCT) recipients.

METHODS

Retrospective review of Legionella cases at MSKCC over a fifteen-year study period from January 1999 and December 2013. Cases were identified by review of microbiology records.

RESULTS

During the study period, 40 cases of Legionella infection were identified; nine among these were due to non-pneumophila species. Most cases occurred during the summer. The majority [8/9, (89%)] of patients with non-pneumophila infection had underlying hematologic malignancy, compared to 18/31 (58%) with Legionella pneumophila infections. Radiographic findings were varied-nodular infiltrates mimicking invasive fungal infection were seen only among patients with hematologic malignancy and hematopoietic stem cell transplant (SCT) recipients and were frequently associated with non-pneumophila infections (50% vs 16%; P = 0.0594). All cases of nodular Legionella pneumonia were found incidentally or had an indolent clinical course.

CONCLUSIONS

Legionella should be considered in the differential diagnosis of nodular lung lesions in immunocompromised patients, especially those with hematologic malignancy and SCT recipients. Most cases of nodular disease due to Legionella are associated with non-pneumophila infections.

A symptom-specific analysis of the effect of high-frequency left or low-frequency right transcranial magnetic stimulation over the dorsolateral prefrontal cortex in major depression

BACKGROUND

We have investigated the efficacy of high-frequency left (HFL) versus low-frequency right (LFR) repetitive transcranial magnetic stimulation (rTMS) in depression, focusing on specific symptoms as possible predictors of outcome for these two different types of stimulation.

METHOD

Seventy-four outpatients with a major depressive episode treated with an adequate antidepressant dosage for at least 4 weeks were included in our study and randomly assigned to two different groups: HFL or LFR rTMS. The Hamilton Rating Scale for Depression (HAM-D) items were pooled into 6 factors to evaluate specific symptoms as possible predictors of response.

RESULTS

Twenty-one out of 32 patients (65.6%) and 24 out of 42 patients (57.1%) were responders in the HFL and LFR groups, respectively. No significant difference in response rate was observed. Considering the whole sample, we found an inverse correlation between activity and HAM-D score reduction and a significant positive relation between somatic anxiety and outcome. An inverse correlation between psychic anxiety and HAM-D score reduction emerged considering the HFL group. In the LFR group, there was a significant negative relationship between baseline activity and the outcome.

CONCLUSION

These findings support the hypothesis that LFR rTMS could be as effective as HFL rTMS and more suitable for patients with a higher anxiety degree, particularly in bipolar patients.

Angiotensin Converting Enzyme Inhibitors and Angiotensin Receptor Blockers May Reduce Breast Cancer Recurrence

There have been epidemiologic and biochemical findings alluding to the role of angiotensin converting enzyme inhibitors(ACEIs) and angiotensin receptor blockers(ARBs) in reducing the risk of developing cancer. To date, there exists no study that reported any relationship between their use and the risk of cancer recurrence. Thus, we investigated the associations between the use of ACEI/ARB and the risk of tumor recurrence among breast cancer patients without any evidence of disease.We reviewed the medical records of female patients diagnosed with stage II/III breast cancer in Albert Einstein Medical Center between 1999 and 2005 and later reached no evident disease (NED) stage after curative therapy. Follow up period was from 1999 to 2008 with mean and maximum being 4.4 years and 9.8 years, respectively. ACEI/ARB user was defined as patients taking the medication in NED stage for at least 6 months. Multivariate analyses were performed using logistic regression and Cox proportional hazard model.Of 707 cancer patients and of 335 cancer patients with hypertension, 164, representing 23.3% of total and 49.0% of those with hypertension were prescribed ACEI/ARB. ACEI/ARB use was associated with older age (P&lt;0.001), postmenopausal status (P&lt;0.001), and diabetes (P&lt;0.01). Fourteen percent (23/164) of ACEI/ARB users developed cancer recurrence, while 23.3% (125/541) of nonusers developed a recurrence (odds ratio [OR], 0.54; 95% confidence interval [CI], 0.33-0.97; P=0.01). Kaplan-Meier survival analysis revealed that ACEI/ARB use was related to disease-free survival benefit (log-rank test P&lt;0.01). Five year disease-free survival for ACEI/ARB users was 0.85 compared with 0.76 for nonusers (P&lt;0.01). Adjusting for statistically significant variables above, ACEI/ARB use was associated with reduced risk of developing recurrence not only in all breast cancer patients but also when they were compared to a subset of the nonusers who had hypertension (AHR, 0.41; 0.23-0.80; P&lt;0.01). While ACEI/ARB use was not associated with reduced mortality in all breast cancer patients (AHR, 1.01; 95% CI: 0.61-1.65; P=0.36; log-rank test P=0.52), it was when compared to the subset of patients with hypertension (AHR, 0.43; 95% CI, 0.25-0.68; P&lt;0.01; log-rank test P&lt;0.01).The use of ACEI/ARB is related to reduced risk of developing recurrence in patients with breast cancer. This result provides clinical evidence, in accordance with existing biochemical and epidemiologic data, that antagonizing angiotensin system is inversely associated with tumor recurrence. However, prospective randomized trials are needed to validate this finding.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3121.

High-power diode-pumped Yb3+:CaF2 femtosecond laser

We report what is believed to be the first demonstration of a high-power passively mode-locked diode-pumped femtosecond laser based on an Yb3+:CaF2 single crystal, directly pumped by a 15-W fiber-coupled laser diode. With a 5-at. % Yb3+ -doped sample and prisms for dispersion compensation we obtained pulses as short as 150 fs, with 880 mW of average power and up to 1.4-W average output power, with a pulse duration of 220 fs, centered at 1049 nm. The laser wavelength could be tuned from 1040 to 1053 nm in the femtosecond regime. Using chirped mirrors for dispersion compensation, the oscillator provided up to 1.74 W of average power, with a pulse duration of 230 fs, corresponding to a pulse energy of 20 nJ and a peak power of 85 kW.

High-power tunable diode-pumped Yb3+:CaF2 laser

Results of diode-pumped cw laser operation of an Yb3+:CaF2 single crystal are reported for what is to our knowledge the first time. With a 5-at.% Yb3+ -doped sample we obtained 5.8-W output power at 1053 nm for 15 W of incident power at 980 nm. The laser wavelength could be tuned from 1018 to 1072 nm, and a small-signal gain as high as 1.8 was achieved, showing the great potential of Yb3+:CaF2 as an amplifier medium for femtosecond pulses.

Effects of fluvoxamine treatment on the in vivo binding of [F-18]FESP in drug naive depressed patients: a PET study

This study investigates the effect of chronic treatment with Fluvoxamine, a potent and specific serotonin reuptake sites inhibitor (SSRI), on 5HT(2) serotonin and D(2) dopamine receptors in the brain of drug naive unipolar depressed patients. Drug effect was evaluated in different cortical areas and in the basal ganglia by positron emission tomography (PET) and fluoro-ethyl-spiperone ([(18)F]FESP), an high affinity 5HT(2) serotonin and D(2) dopamine receptors antagonist. Patients underwent a PET study at recruitment and after clinical response to Fluvoxamine treatment. Nine of the 15 patients recruited completed the study. Fluvoxamine treatment significantly improved clinical symptoms and modified [(18)F]FESP binding in the frontal and occipital cortex of all of the nine patients who completed the study; in these regions a mean 31% increase in the in vivo [(18)F]FESP binding was found (P < 0.01). On the contrary, no significant changes in the in vivo [(18)F]FESP binding were found in the basal ganglia where [(18)F]FESP binds mainly to D(2) dopamine receptors. Chronic treatment with Fluvoxamine significantly increases the in vivo binding of [(18)F]FESP in the frontal and occipital cortex of drug naive unipolar depressed patients. The increase of the in vivo binding of [(18)F]FESP may reflect a modification in 5HT(2) binding capacity secondary to changes in cortical serotonin activity.

Total sleep deprivation combined with lithium and light therapy in the treatment of bipolar depression: replication of main effects and interaction

The clinical usefulness of total sleep deprivation (TSD) in the treatment of bipolar depression is hampered by a high-rate short-term relapse. Previous literature has suggested that both long-term lithium treatment and light therapy could successfully prevent relapse. We randomized 115 bipolar depressed inpatients to receive three cycles of TSD, alone or in combination with morning light exposure, given at an intensity of 150 or 2500 lux. Forty-nine patients were undergoing long-term treatment with lithium salts (at least 6 months), while 66 patients were taking no psychotropic medication. Mood was self-rated by the Visual Analogue Scale three times a day during treatment. The results showed that both light therapy and ongoing lithium treatment significantly enhanced the effects of TSD on the perceived mood, with no additional benefit when the two treatments were combined. Subjective sleepiness during TSD, as rated by the self-administered Stanford Sleepiness Scale, was significantly reduced by light exposure, and was correlated with the outcome. This study confirms the possibility of obtaining a sustained antidepressant response to TSD in bipolar patients.

Simultaneous determination of human plasma levels of four selective serotonin reuptake inhibitors by high-performance liquid chromatography

A reversed-phase high-performance liquid chromatography (HPLC) method with fluorimetric detection, which allows the simultaneous determination of plasma concentrations of four selective serotonin reuptake inhibitors (SSRIs) is presented. Fluvoxamine, paroxetine, sertraline, and fluoxetine were extracted from plasma with ethyl acetate and then derivatized with dansyl chloride. The analytes were separated using Hypersyl ODS C18 (5 microm) 250 x 4.6 mm column (ThermoQuest, Runcorn, UK). For continuous gradient separation, the mobile phase consists of two eluents, acetonitrile and potassium phosphate buffer (10 mmol/L, pH 7.2) at total flow rate of 1.5 mL/min. Detection was carried out at lambda exc = 366 nm and lambda em = 490 nm. The authors found recoveries of 90% to 95% for fluvoxamine, 94% to 100% for paroxetine, 88% to 95% for sertraline, 93% to 100% for fluoxetine, and 97% to 100% for internal standard (nortriptyline). Imprecision of the method ranged from 2.5% to 8.9%. The assay was linear from 10 to 1500 ng/mL for sertraline, and from 5 to 1500 ng/mL for the other drugs. The authors conclude that this method is suitable for monitoring antidepressant therapy. In addition, the authors report the effects of adding paroxetine to fluvoxamine on plasma levels in a group of patients in combined drug therapy.

Faster onset of action of fluvoxamine in combination with pindolol in the treatment of delusional depression: a controlled study

This double-blind, controlled study was undertaken to investigate whether the addition of pindolol could improve the therapeutic response to fluvoxamine of depressed patients with psychotic features. After a 1-week placebo run-in period, 72 patients received fluvoxamine 300 mg/day in combination with placebo or pindolol 7.5 mg/day. At study completion, 28 (80%) of 35 patients treated with fluvoxamine plus placebo and 29 (80.5%) of 36 patients treated with fluvoxamine plus pindolol were categorized as responders (reduction of their score on the 21-item Hamilton Rating Scale for Depression to 8 or less and on the Dimension for the Delusional Experience Rating Scale to 0). In the third and fourth weeks, the response rates were significantly superior in the fluvoxamine plus pindolol group (p = 0.0001, p = 0.023, respectively). Treatment response seemed to be unrelated to the demographic and the clinical characteristics recorded. No significant difference was found comparing plasma levels of fluvoxamine between groups, thus excluding a pharmacokinetic interaction. Other than mild nausea and sedation in a few patients, treatments were well tolerated. No medically significant adverse events occurred. Depressed patients with psychotic features who were administered pindolol experienced a more rapid improvement during fluvoxamine treatment. Thus, the combination of fluvoxamine with pindolol may be a useful pharmacologic strategy in the treatment of this disorder. A rapid clinical response in such patients is of relevance in clinical practice as well as in economic fields, given the direct and indirect costs of depression.

Plasma tryptophan levels and tryptophan/neutral amino acid ratios in obsessive-compulsive patients with and without depression

We have studied fasting plasma tryptophan (TRP) levels and tryptophan/large neutral amino acid (TRP/LNAA) ratios in 12 patients with obsessive-compulsive disorder (OCD) and 12 patients with OCD and a coexisting current diagnosis of major depressive disorder (OCD-MDD). Assessments were made at baseline and after 6 weeks of treatment with fluvoxamine. OCD-MDD patients had significantly lower baseline TRP levels and TRP/LNAA ratios than OCD patients. After 6 weeks of fluvoxamine treatment, OCD-MDD patients had significant increases in plasma TRP and TRP/LNAA ratio, whereas OCD patients had non-significant decreases. Our data suggest that a major depressive syndrome could be a state variable affecting the changes in plasma TRP and TRP/LNAA ratio in OCD patients.

Sleep deprivation hastens the antidepressant action of fluoxetine

Among ten bipolar depressed patients admitted to our psychiatric ward, five patients were treated with fluoxetine alone and five subjects were treated with fluoxetine in association with total sleep deprivation (TSD) in order to evaluate the effect of the interaction between the administration of the serotonergic antidepressant compound fluoxetine and repeated cycles of TSD. Patients treated with fluoxetine plus repeated TSD showed a faster amelioration of depressive symptomatology compared with the other group. We discuss our findings hypothesizing an enhancement in dopaminergic and possibly in serotonergic transmission due to repeated TSD adding to the increase in serotonergic transmission due to fluoxetine medication.

Tryptophan depletion in obsessive-compulsive patients

Twelve patients with obsessive-compulsive disorder were studied after the administration of a mixture of amino acids devoid of tryptophan (TRP) or a mixture containing all the essential amino acids, in a double-blind, crossover design. The TRP-free mixture caused a marked depletion of plasma TRP. After TRP decrease, mean ratings of obsessions and compulsions, measured by Visual Analogue Scales (VAS) ratings, did not worsen. In contrast with other reports in literature, TRP depletion also failed to alter mood in our subjects.

Decrease in plasma phenylalanine and tyrosine after phenylalanine-tyrosine free amino acid solutions in man

After an overnight fast, 5 male healthy subjects ingested increasing amounts of a solution containing a fixed proportion of seven essential amino acids (L-isoleucine, 13.3%; L-leucine, 21.0%; L-lysine, 15.2%; L-methionine, 21.0%; L-threonine, 9.5%; L-tryptophan, 4.8% and L-valine, 15.2%) and lacking phenylalanine and tyrosine. The solutions caused a rapid fall in plasma phenylalanine and tyrosine which was proportional to the total amount of amino acids ingested. Following the highest dose administered (31.5 g) plasma phenylalanine and tyrosine fell to a minimum of, respectively, 12.7% and 29.8% the initial levels and remained markedly reduced at 6 hours after treatment. The decrease of tyrosine and phenylalanine levels was associated with a decrease of systolic and diastolic arterial pressure.

Predictive value of tryptophan/large neutral amino acids ratio to antidepressant response

The molar ratio of total plasma tryptophan to the sum of other large neutral amino acids (viz., valine, isoleucine, leucine, tyrosine, phenylalanine), thought to reflect brain serotonin formation, was estimated in 69 patients with major depression before and after 1 week of treatment with different serotonin reuptake inhibitors, fluvoxamine (n = 28), fluoxetine (n = 10), citalopram (n = 7), mixed serotonin-noradrenaline reuptake inhibitor amitriptyline (n = 11), clomipramine (n = 8) and the preferentially noradrenaline reuptake inhibitor, nortriptyline (n = 5). A significant difference among 'good', 'intermediate' and 'poor' responders for the percentual variation of tryptophan/large neutral amino acids ratio after 1 week of therapy was found, while pretreatment values of tryptophan/large neutral amino acids ratio, basal Hamilton Depression Rating Scale scores and its percentual variation after 1 week of therapy did not show any significant differences. These results suggest that the percentual variation of tryptophan/large neutral amino acids ratio could be a useful tool in predicting drug response.

Neutral amino acid availability in two major psychiatric disorders

1. Evidence suggests catecholamines and indoleamines may play a role in the pathogenesis of several psychiatric disorders. These neurotransmitters (i.e. dopamine, norepinephrine and serotonin) are synthesized within the human brain from their precursors, the aromatic large neutral amino acids tyrosine and tryptophan. Other large neutral amino acids, namely valine, isoleucine, leucine and phenylalanine affect precursor availability by competing with tryptophan and tyrosine for the transport system across the blood brain barrier. 2. The authors evaluated the brain availability of L-tryptophan and tyrosine in a sample of psychiatric patients with a diagnosis of major depression and schizophrenia. 3. The present results suggest a possible usefulness of Tryptophan/Large Neutral Amino Acids ratio in distinguishing major depression from schizophrenia, while Tyrosine/Large Neutral Amino Acids ratio shows a very limited usefulness. The absolute need of powerful and accurate statistical analysis to evaluate the power of a biological test clearly stands out from the present study.

Plasma tryptophan to large neutral amino acids ratio and therapeutic response to a selective serotonin uptake inhibitor

The molar ratio of total plasma tryptophan (Trp) to the sum of the other large neutral amino acids (LNAAs), thought to reflect brain serotonin (5-HT) formation, was estimated in 47 patients with major depression (unipolar and bipolar) before and after 6 weeks of treatment with a serotonin uptake inhibitor, fluvoxamine. We found a significant difference between responders (n = 39) and nonresponders (n = 8) for the pre- and in-treatment plasma Trp to LNAAs ratios. In contrast, there were no differences between the two groups for the mean plasma steady-state fluvoxamine levels. These findings suggest that a specific plasma amino acid profile may be a useful indicator of good clinical response to a selective 5-HT uptake inhibitor.

Serine and glycine metabolism in schizophrenic patients

1. The brain glycine is almost exclusively derived from serine via serine-hydroxymethyltransferase. 17 males schizophrenic inpatients and 10 males healthy volunteers were submitted to the serine tolerance test. 2. Plasma serine and glycine concentration were evaluated before and after 1, 2, 3, 4 hours of an oral load with L-serine to test the interconversion between the two amino acids. 3. The authors did not find any significant difference between schizophrenic patients and control group and concluded that the enzyme serine-hydroxymethyltransferase is not deficient in the conversion of serine to glycine in schizophrenic patients as suggested by other authors.

Plasma tryptophan levels and plasma tryptophan/neutral amino acids ratio in patients with mood disorder, patients with obsessive-compulsive disorder, and normal subjects

Fasting plasma tryptophan (TRP) levels and ratios of total plasma tryptophan to the sum of five large neutral amino acids (LNAAs)--tyrosine, phenylalanine, leucine, isoleucine, and valine--that compete with tryptophan for passage across the blood-brain barrier were found to be significantly lower in a group of 28 patients with major depression compared with 29 normal subjects and 21 patients with obsessive-compulsive disorder (OCD). The OCD group was divided in two subgroups: patients with OCD alone and patients with a co-diagnosis of major depression. Since it has been considered that these biological parameters reflect brain tryptophan and serotonin levels, our results suggest their importance in relation to the presence or absence of depressive symptoms. The values of the other LNAAs and their sum did not differ significantly among the groups.

Amino acid patterns in schizophrenia: some new findings

Blood concentrations of various amino acids were measured in schizophrenic patients and control subjects. Significantly higher blood concentrations of glycine, glutamate, and serine were found in the schizophrenic patients. Glycine was abnormally elevated in subjects with paranoid or undifferentiated schizophrenia, but not in disorganized patients. Since glutamate, glycine, and serine play a complex role in the regulation of N-methyl-D-aspartate (NMDA) receptors, which are important in the control of normal cognitive processes, we hypothesized that the elevated levels of these amino acids might disrupt the normal functioning of NMDA receptors and might be involved in the pathophysiology of schizophrenia.

Biochemical investigation of histidinemia in schizophrenic patients

Our results suggest that the association between the clinical diagnosis of schizophrenic disorder and heterozygosis for histidinemia is not a chance one. The real meaning of this relationship has to be further investigated.

Effect of lithium treatment on the GH-clonidine test in affective disorders

The effects of short-term lithium (Li) administration on alpha 2-adrenoceptor sensitivity was studied in 10 healthy volunteers and in 15 patients with normothymic, phasic depressive disorders. The GH-clonidine test was used to examine alpha 2-adrenoceptor sensitivity, administered before and after Li treatment (600 mg/day for 7 days in controls and for 15 days in patients). Before treatment, the GH response to clonidine in the patients was blunted, and afterwards it tended to increase in the patients and it was significantly decreased in the controls. The difference between the response in the two groups was significant and was correlated both with the diagnosis and the pretreatment GH response to the stimulus. The opposing pattern of the response in patients and controls to Li administration suggests that the drug exerts a modulatory effect on alpha 2-adrenoceptor sensitivity, with up or down regulation inversely correlated with pretreatment status.

Increased concentrations of various amino acids in schizophrenic patients. Evidence for heterozygosity effects?

The hypothesis is examined that heterozygosity for amino acid disorders (AAD) is a genetic component of susceptibility for schizophrenic psychoses. To detect possible heterozygotes, urinary and blood amino acid levels were analyzed in a sample of subjects with a diagnosis of schizophrenia and in their biological parents and compared with those of a sample of healthy volunteers. The results showed increased blood and urinary levels of certain amino acid in those patients who have at least one parent with the same amino acid abnormality. This finding points to the possibility of heterozygosity for AAD in schizophrenic patients.

Red blood cell plasma Li ratio variability in affective patients

In the light of the existence of controversial reports on the stability of Li ratio, we investigated a group of affective patients wishing to verify intraindividual stability of this parameter in the different phases of the disease, that is normothymia and manic and depressive episodes. We found lower Li ratios for the periods preceding any relapse. Further, we analyzed whether or not some epidemiological factors, such as polarity, sex, actual age, age of onset, might affect interindividual variability of the Li ratio. We found that they did not as single factors. Interaction between polarity and the presence of relapses appeared to significantly affect the Li ratio.