Bicavitary effusion in cats: retrospective analysis of signalment, clinical investigations, diagnosis and outcome

OBJECTIVES

The aim of this study was to describe the clinical and diagnostic findings and outcome of cats with bicavitary effusion presenting to a referral centre.

METHODS

Medical records of cats presenting with bicavitary effusion were identified and their history, physical examination findings, clinicopathological data, diagnostic imaging findings, aetiology of bicavitary effusions (cardiac disease, neoplasia, infectious disease, sterile inflammatory disease, severe hypoalbuminaemia, trauma, coagulopathy or 'open' if no definitive diagnosis was reached) and outcome were recorded. Cox regression analysis was performed to identify independent predictors of death in cats with bicavitary effusion. Kaplan-Meier curves were generated for survival analysis.

RESULTS

In total, 103 cats with bicavitary effusion were included. Neoplasia and cardiac disease were the most common aetiologies of bicavitary effusion, in 21 (20.4%) and 20 (19.4%) cats, respectively, followed by infectious disease (n = 11, 10.7%), trauma (n = 13, 12.6%), hypoalbuminaemia (n = 6, 5.8%), sterile inflammatory disease (n = 4, 3.9%) and coagulopathy (n = 1, 1.0%). The median survival time for all cats with bicavitary effusion was 3 days. Cats with a neoplastic aetiology had a 2.03 times greater risk of death compared with cats in which no diagnosis was achieved. Neoplasia (P = 0.030) and pedigree breed status (P = 0.016) were independent predictors of death in the multivariable Cox regression model.

CONCLUSIONS AND RELEVANCE

This study highlights that bicavitary effusions in cats generally carry a guarded to poor prognosis, particularly if neoplasia is the underlying aetiology or if the cat is a pedigree breed. Cardiac disease appeared to be associated with a better prognosis, suggesting that assessment for congestive heart failure should be considered early when evaluating cats with bicavitary effusion. The prognosis for cats with feline infectious peritonitis is likely to be markedly improved by the advent of novel antiviral drugs, compared with the historical cohort of cats presented here.

Nephrotoxicity of Vancomycin in Combination With Beta-Lactam Agents: Ceftolozane-Tazobactam vs Piperacillin-Tazobactam

BACKGROUND

Vancomycin (VAN)-associated acute kidney injury (AKI) is increased when VAN is combined with certain beta-lactams (BLs) such as piperacillin-tazobactam (TZP) but has not been evaluated with ceftolozane-tazobactam (C/T). Our aim was to investigate the AKI incidence of VAN in combination with C/T (VAN/C/T) compared with VAN in combination to TZP (VAN-TZP).

METHODS

We conducted a multicenter, observational, comparative study across the United States. The primary analysis was a composite outcome of AKI and risk, injury, failure, loss, end stage renal disease; Acute Kidney Injury Network; or VAN-induced nephrotoxicity according to the consensus guidelines. Multivariable logistic regression analysis was conducted to adjust for confounding variables and stratified Kaplan-Meir analysis to assess the time to nephrotoxicity between the 2 groups.

RESULTS

We included VAN/C/T (n = 90) and VAN-TZP (n = 284) at an enrollment ratio of 3:1. The primary outcome occurred in 12.2% vs 25.0% in the VAN-C/T and VAN-TZP groups, respectively (P = .011). After adjusting for confounding variables, VAN-TZP was associated with increased odds of AKI compared with VAN-C/T; with an adjusted odds ratio of 3.308 (95% confidence interval, 1.560-6.993). Results of the stratified Kaplan-Meir analysis with log-rank time-to-nephrotoxicity analysis indicate that time to AKI was significantly shorter among patients who received VAN-TZP (P = .004). Cox proportional hazards analysis demonstrated that TZP was consistent with the primary analysis (P = .001).

CONCLUSIONS

Collectively, our results suggest that the AKI is not likely to be related to tazobactam but rather to piperacillin, which is a component in VAN-TZP but not in VAN-C/T.

The microvascular endothelial glycocalyx: An additional piece of the puzzle in veterinary medicine

The endothelial glycocalyx (eGlx) is a critically important structure lining the luminal surface of endothelial cells. There is increasing evidence, in human patients and animal models, for its crucial role in the maintenance of health. Moreover, its damage is associated with the pathogenesis of multiple disease states. This review provides readers with an overview of the eGlx; summarising its structure, essential functions, and evidence for its role in disease. We highlight the lack of studies regarding the eGlx in cats and dogs, particularly in naturally occurring diseases. Importantly, we discuss techniques to aid its study, which can be applied to veterinary species. Finally, we present targeted therapies aimed at preserving, and in some cases, restoring damaged eGlx.

Circulating hyaluronan as a marker of endothelial glycocalyx damage in dogs with myxomatous mitral valve disease and dogs in a hypercoagulable state

The endothelial glycocalyx (eGlx) lines the luminal surface of endothelial cells, maintaining vascular health. Glycocalyx damage is pathophysiologically important in many diseases across species however few studies have investigated its breakdown in naturally occurring disease in dogs. The aims of the study were to investigate eGlx damage in dogs with myxomatous mitral valve disease (MMVD) diagnosed on echocardiography, and dogs in a hypercoagulable state diagnosed using thromboelastography (TEG), by measuring serum hyaluronan concentrations. Serum hyaluronan was quantified in dogs with MMVD (n = 27), hypercoagulability (n = 21), and in healthy controls dogs (n = 18). Serum hyaluronan concentrations were measured using a commercially-available ELISA validated for use in dogs. Hyaluronan concentrations were compared among groups using Kruskal-Wallis tests, and post-hoc with Dunn’s tests. Serum hyaluronan concentrations (median [range]) were significantly increased in dogs with MMVD (62.4 [22.8–201] ng/mL; P = 0.031) and hypercoagulability (92.40 [16.9–247.6] ng/mL; P < 0.001) compared to controls (45.7 [8.7–80.2] ng/mL). Measurement of serum hyaluronan concentration offers a clinically applicable marker of eGlx health and suggests the presence of eGlx damage in dogs with MMVD and dogs in a hypercoagulable state.

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Few studies have investigated endothelial glycocalyx breakdown in disease in dogs.

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Serum hyaluronan is a clinically applicable marker of endothelial glycocalyx health.

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Serum hyaluronan was significantly increased in dogs with mitral valve disease.

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Serum hyaluronan was significantly increased in dogs in a hypercoagulable state.

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Increased serum hyaluronan may indicate glycocalyx shedding in these diseases.

Visualising the endothelial glycocalyx in dogs

The endothelial glycocalyx (eGlx) lines the luminal surface of endothelial cells. It is critical in maintaining vascular health and when damaged contributes to many diseases. Its fragility makes studying the eGlx technically challenging. The current reference standard for eGlx visualisation, by electron microscopy using glutaraldehyde/Alcian blue perfusion fixation, has not been previously reported in dogs. Established techniques were applied to achieve visualisation of the eGlx in the microvasculature of reproductive tissue in five healthy dogs undergoing elective neutering. Uterine and testicular artery samples underwent perfusion fixation, in the presence of Alcian blue, prior to transmission electron microscopy imaging. Image processing software was used to determine eGlx depth. EGlx was visualised in the arteries of two dogs, one testicular and one uterine, with median (range) eGlx depths of 68.2 nm (32.1–122.9 nm) and 47.6 nm (26.1–129.4 nm) respectively. Study of the eGlx is technically challenging, particularly its direct visualisation in clinical samples. Further research is needed to develop more clinically applicable techniques to measure eGlx health.

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Canine glycocalyx has not previously been visualised using the reference technique.

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The endothelial glycocalyx was visualised in dog uterine and testicular arteries.

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Direct visualisation of the endothelial glycocalyx was technically challenging.

Preliminary demonstration of benchtop NMR metabolic profiling of feline urine: chronic kidney disease as a case study

Objective

The use of benchtop metabolic profiling technology based on nuclear magnetic resonance (NMR) was evaluated in a small cohort of cats with a view to applying this as a viable and rapid metabolic tool to support clinical decision making.

Results

Urinary metabolites were analysed from four subjects consisting of two healthy controls and two chronic kidney disease (CKD) IRIS stage 2 cases. The study identified 15 metabolites in cats with CKD that were different from the controls. Among them were acetate, creatinine, citrate, taurine, glycine, serine and threonine. Benchtop NMR technology is capable of distinguishing between chronic kidney disease case and control samples in a pilot feline cohort based on metabolic profile. We offer perspectives on the further development of this pilot work and the potential of the technology, when combined with sample databases and computational intelligence techniques to offer a clinical decision support tool not only for cases of renal disease but other metabolic conditions in the future.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05888-y.

129. Safety and Cost-effectiveness Analysis Outpatient Continuous Parenteral Antibiotics via a Disposable Elastomeric Pump at Two County Hospitals in Houston, Texas

Background

Outpatient parenteral antibiotic therapy (OPAT) is a therapeutic option for patients who require longer intravenous (IV) antimicrobial courses, yet do not need to remain hospitalized. HarrisHealth system OPAT programs implement a disposable elastomeric continuous infusion pump (eCIP) for IV antibiotics. Here we report the clinic-demographic features, outcomes of a cohort of patients receiving OPAT via eCIP (OPAT-eCIP), as well as the cost-effectiveness of OPAT in comparison to standard inpatient care.

Methods

We retrospectively obtained the clinic-demographic characteristics and outcomes of 91 patients discharged from HarrisHealth-affiliated hospitals from December 2018 to February 2021 who underwent OPAT-eCIP. We then compared the total costs associated with home OPAT-eCIP care with that of an equivalent of inpatient IV antimicrobial treatment based on previous studies.

Results

We identified 481 total OPAT patients; 91 (18.9%) received intravenous antibiotics via eCIP, with two initiating therapy outpatient. In total, 1925 days of IV antimicrobial therapy were administered outpatient by OPAT-eCIP, with a median treatment course of 12 days. Eighty-three (92.2%) patients completed their antimicrobial course, with 85 (93.4%) cured of respective infections (Table 1). Antimicrobial-associated adverse events and PICC line associated complications were 6.6% and 14.3% respectively. 30-day hospital readmission rates were under 10% with 21 patients (23.1%, 28 total visits) presenting to the emergency room over the course of IV therapy. Estimated costs of OPAT-eCIP care over the study period ranged from &417,000-&576,750 with costs of equivalent inpatient care estimated at &2,945,250 to &3,927,000; estimated overall cost savings of OPAT-eCIP were &2,368,500 to &3,509,900 (Table 2).

Table 1. Characteristics and Outcomes of Patients Receiving Continuous IV Antibiotics via Disposable Elastomeric Pump

Conclusion

OPAT-eCIP therapy in a cohort of patients was highly effective and well-tolerated. While ED visit frequency indicates the necessity of close patient monitoring, low 30-day hospital readmission rates were encouraging. Along with the above, the significant cost savings demonstrated when compared with standard inpatient antimicrobial therapy suggest that OPAT-eCIP should be increasingly utilized as an effective therapeutic option.

Disclosures

All Authors: No reported disclosures

Characteristics, safety and cost-effectiveness analysis of self-administered outpatient parenteral antibiotic therapy via a disposable elastomeric continuous infusion pump at two county hospitals in Houston, Texas, United States

WHAT IS KNOWN AND OBJECTIVE

Outpatient parenteral antibiotic therapy (OPAT) is an attractive option for patients who require parenteral antimicrobials as outpatients. Few OPAT studies have assessed the impact of IV antibiotic therapy via elastomeric continuous pumps, with most having been conducted outside the United States and few in county hospitals. The OPAT program in Harris Health system, the county hospital system of Houston, Texas, United States, has implemented a disposable elastomeric continuous infusion pump (eCIP) for self-administered intravenous antibiotics (s-OPAT) since December 2018. Our goal was to describe the clinical characteristics of patients discharged with an eCIP, as well as the safety and cost-effectiveness of this pump.

METHODS

We retrospectively analysed patients discharged from Harris Health hospitals between 12/2018 and 02/2021 with s-OPAT via eCIP at home. We extracted various patient characteristics and outcomes related to OPAT.

RESULTS AND DISCUSSION

Among 481 OPAT patients during the study period, 91 patients received s-OPAT via eCIP. A total of 1925 days of s-OPAT were administered at home, with a median duration of 12 days. Eighty-three patients (93.4%) achieved a cure from infection, six patients (6.6%) had side effects, and nine patients (9.9%) experienced 30-day hospital readmission. Twenty-two patients (24.2%) presented to the ED during s-OPAT, with 13 patients (14.3%) presenting with PICC line concerns. We estimated that s-OPAT via eCIP saved $2,360,500 to $3,503,900 compared to inpatient-only therapy.

WHAT IS NEW AND CONCLUSION

Our study showed that patients with s-OPAT via eCIP had a high cure rate with a relatively low incidence of side effects and 30-day hospital readmission. ED visits during therapy were relatively high, which indicates the necessity of close patient monitoring via the OPAT program. eCIP appears to be a good option to facilitate an early disposition of patients in county hospitals.

Reproductive seasonality and rate of increase of wild sambar deer (Rusa unicolor) in a new environment, Victoria, Australia

Sambar (Rusa unicolor) are the most numerous and rapidly expanding of Australia's six introduced deer species, however, there is little information about the reproductive biology of sambar deer in their natural habitat. To better predict and manage wild sambar populations in Australia it is important to understand their reproductive seasonality and rate of population growth. From results of the present study, there is reporting of field estimates of age at first breeding, reproductive lifespan, juvenile survival, adult bodyweights and fecundity to derive estimates of the current and intrinsic rates of increase for sambar in Victoria, Australia. Mean age of first reproduction was estimated to be 1.8 years, approximately 80 % of hinds calved between April and August, juvenile survival was estimated as 0.81 and age of last reproduction 12.75 years. Seasonality of reproduction is apparently compressed at 36° latitude compared to sambar at the equator indicating a response to photoperiod. Demographic data were used to estimate the current rate of growth of the Victorian population using the two stage Lotke-Euler equation and age-specific schedules of survival and fecundity in a lifetable. These estimates of r were 0.21 and 0.14, respectively, inferring annual rates of population increase of 24 % and 15 %. These data are in the context of a population which, even though there is a marked harvesting, is reportedly growing and dispersing northwards. Suggestions for how this information can inform management decisions directed at the conservation for sustainable use and/or population reduction in Australia are made.

Blocking matrix metalloproteinase-mediated syndecan-4 shedding restores the endothelial glycocalyx and glomerular filtration barrier function in early diabetic kidney disease

The endothelial glycocalyx is a key component of the glomerular filtration barrier. We have shown that matrix metalloproteinase (MMP)-mediated syndecan 4 shedding is a mechanism of glomerular endothelial glycocalyx damage in vitro, resulting in increased albumin permeability. Here we sought to determine whether this mechanism is important in early diabetic kidney disease, by studying streptozotocin-induced type 1 diabetes in DBA2/J mice. Diabetic mice were albuminuric, had increased glomerular albumin permeability and endothelial glycocalyx damage. Syndecan 4 mRNA expression was found to be upregulated in isolated glomeruli and in flow cytometry-sorted glomerular endothelial cells. In contrast, glomerular endothelial luminal surface syndecan 4 and Marasmium oreades agglutinin lectin labelling measurements were reduced in the diabetic mice. Similarly, syndecan 4 protein expression was significantly decreased in isolated glomeruli but increased in plasma and urine, suggesting syndecan 4 shedding. Mmp-2, 9 and 14 mRNA expression were upregulated in isolated glomeruli, suggesting a possible mechanism of glycocalyx damage and albuminuria. We therefore characterised in detail the activity of MMP-2 and 9 and found significant increases in kidney cortex, plasma and urine. Treatment with MMP-2/9 inhibitor I for 21 days, started six weeks after diabetes induction, restored endothelial glycocalyx depth and coverage and attenuated diabetes-induced albuminuria and reduced glomerular albumin permeability. MMP inhibitor treatment significantly attenuated glomerular endothelial and plasma syndecan 4 shedding and inhibited plasma MMP activity. Thus, our studies confirm the importance of MMPs in endothelial glycocalyx damage and albuminuria in early diabetes and demonstrate that this pathway is amenable to therapeutic intervention. Hence, treatments targeted at glycocalyx protection by MMP inhibition may be of benefit in diabetic kidney disease.

ISFM Consensus Guidelines on the Diagnosis and Management of Feline Chronic Kidney Disease

Practical relevance:

Chronic kidney disease (CKD) is one of the most commonly diagnosed diseases in older cats. In most cats, CKD is also a progressive disease and can be accompanied by a wide range of clinical and clinicopathological changes. These ISFM Consensus Guidelines have been developed by an independent panel of clinicians and academics to provide practical advice on the diagnosis and management of this complex disease.

Clinical challenges:

Although CKD is a common clinical problem in cats, the manifestations of disease vary between individuals. Thus there is a need for careful and repeat evaluation of cats with CKD and adjustment of therapy according to individual needs. In addition to addressing problems arising from CKD and improving quality of life (QoL) for the patient, therapy may also target slowing the underlying progression of disease and hence prolonging life. While maintaining QoL is of paramount importance in our patients, this can be challenging when multiple therapies are indicated. In some cases it is necessary to prioritise therapy, given an understanding of what is likely to most benefit the individual patient.

Evidence base:

In preparing these Guidelines, the Panel has carefully reviewed the existing published literature, and has also graded the quality of evidence for different interventions to help to provide practical recommendations on the therapeutic options for feline CKD. This is a field of veterinary medicine that has benefited from some excellent published clinical research and further research findings will undoubtedly modify the recommendations contained in these Guidelines in the future.

Measurement of glomerular filtration rate in cats

Practical relevance:

Routinely used markers of renal function in clinical practice include urea and creatinine. However, these are insensitive markers, particularly in the early stages of kidney disease. Measurement of glomerular filtration rate (GFR) is regarded as the most sensitive index of functioning renal mass. It may be useful for feline patients in varying clinical scenarios; for example, where a more accurate measurement of renal function may aid diagnosis, to enable response to therapeutic interventions to be more closely monitored, or to evaluate renal function prior to the use of nephrotoxic or renally cleared drugs.

Clinical challenges:

Traditional methods of measuring GFR, such as renal clearance or multisample plasma clearance techniques, are generally impractical for clinical use. Limited sampling and single sample plasma clearance methods using the filtration marker iohexol have been validated in cats. These have the advantages of reduced stress to cats associated with repeated sampling and reduced costs of analysis, and therefore offer greater clinical utility. Attempts to develop an estimated GFR (eGFR) formula similar to that used in human patients have been made in cats, although currently an accurate and reliable formula is not available.

Audience:

This review presents the basis for the theoretical understanding and practical measurement of GFR for any veterinary practitioner wishing to obtain a more accurate and sensitive assessment of renal function than routinely used markers provide.

Evidence base:

The review draws evidence from peer-reviewed publications, the author’s PhD thesis and also clinical experience.

Similar clinical and neuroimaging features in monozygotic twin pair with mutation in progranulin

OBJECTIVE

To report the phenotypic characterization of monozygotic twins with mutations encoding progranulin (PGRN).

METHODS

We studied a twin pair with an exon 4 gene deletion in the PGRN gene. Both twins had clinical and neuropsychological examinations as well as structural MRI and fluorodeoxyglucose PET (FDG-PET) scans. PGRN gene sequencing was performed followed by progranulin ELISA in plasma.

RESULTS

Both twins manifested symptoms within 3 years of each other, with early behavioral, language, dysexecutive, and memory problems. MRI and FDG-PET imaging demonstrated a strikingly similar topography of findings with clear left hemisphere predominance. Serum progranulin levels in both were well below those from a normal population sample.

CONCLUSIONS

Compared with the heterogeneity seen in many families with PGRN mutations, these monozygotic twins demonstrated strong clinical, neuroimaging, and serum progranulin level similarities, demonstrating the importance of shared genetic profiles beyond environmental influences in the symptomatic expression of the disease.

TMEM106B regulates progranulin levels and the penetrance of FTLD in GRN mutation carriers

OBJECTIVES

To determine whether TMEM106B single nucleotide polymorphisms (SNPs) are associated with frontotemporal lobar degeneration (FTLD) in patients with and without mutations in progranulin (GRN) and to determine whether TMEM106B modulates GRN expression.

METHODS

We performed a case-control study of 3 SNPs in TMEM106B in 482 patients with clinical and 80 patients with pathologic FTLD-TAR DNA-binding protein 43 without GRN mutations, 78 patients with FTLD with GRN mutations, and 822 controls. Association analysis of TMEM106B with GRN plasma levels was performed in 1,013 controls and TMEM106B and GRN mRNA expression levels were correlated in peripheral blood samples from 33 patients with FTLD and 150 controls.

RESULTS

In our complete FTLD patient cohort, nominal significance was identified for 2 TMEM106B SNPs (top SNP rs1990622, p(allelic) = 0.036). However, the most significant association with risk of FTLD was observed in the subgroup of GRN mutation carriers compared to controls (corrected p(allelic) = 0.0009), where there was a highly significant decrease in the frequency of homozygote carriers of the minor alleles of all TMEM106B SNPs (top SNP rs1990622, CC genotype frequency 2.6% vs 19.1%, corrected p(recessive) = 0.009). We further identified a significant association of TMEM106B SNPs with plasma GRN levels in controls (top SNP rs1990622, corrected p = 0.002) and in peripheral blood samples a highly significant correlation was observed between TMEM106B and GRN mRNA expression in patients with FTLD (r = -0.63, p = 7.7 × 10(-5)) and controls (r = -0.49, p = 2.2 × 10(-10)).

CONCLUSIONS

In our study, TMEM106B SNPs significantly reduced the disease penetrance in patients with GRN mutations, potentially by modulating GRN levels. These findings hold promise for the development of future protective therapies for FTLD.

Influences of a Relaxation Intervention on Perceived Stress and Power Spectral Analysis of Heart Rate Variability

This study was designed to determine whether power spectral analysis (PSA) of heart rate variability (HRV) can detect change in autonomic tone following a relaxation intervention called therapeutic touch (TT). Thirty healthy subjects underwent TT by one of three TT practitioners using the steps developed by Krieger and Kunz (The Therapeutic Touch, Prentice-Hall, 1979). Both subjects and TT practitioners were monitored by continuous electrocardiographic monitoring (Holter) before (15 minutes), during, and after (15 minutes) TT was administered. Subjects and TT practitioners completed a visual analogue scale (VAS) of perceived stress before and after TT. Change scores for VAS and PSA of high-frequency/low-frequency (HF/LF) ratios were compared for the 2-minute interval before TT began and the end of TT and the end of the recovery period, using t tests. VAS scores decreased (less stress) from before to after TT for both subjects (p < 0.0005) and TT practitioners (p < 0.0005). Mean HF/LF ratios increased significantly to reflect greater parasympathetic dominance from before TT to the end of treatment for subjects (p = 0.006), but not for TT practitioners. However, further analysis revealed that this change was due to an exaggerated HF/LF response from four outliers (p < 0.0005). Data collected in this study did not reveal differences between these four subjects and the rest of the sample. There were no significant changes in HF/LF ratios from the end of TT to end of recovery for either group. Further research is needed to determine why some subjects may have greater change in autonomic tone in response to relaxation in order to be able to predict who will demonstrate physiologic response to relaxation interventions.

Experiences of patients and significant others with automatic implantable cardioverter defibrillators after discharge from the hospital

Sudden cardiac death (SCD) is a leading cause of mortality in this country. The automatic implantable cardioverter defibrillator (AICD) is a technology which has proven successful in reducing the risk of SCD in patients who qualify for it. However, little is known about how individuals adjust to living with the device. This field study used a focus group technique to investigate the question "What are the experiences of patients and their significant others (S.O.) in the time since being discharged from the hospital with an AICD?" Fifteen AICD recipients and 14 S.O.s each attended one of three focus groups which were tape recorded. Data from the transcriptions were analyzed by a combination of content analysis and ethnographic summary. The major concerns of the patients were [Physiologic], the sensations of being shocked, medications, trouble sleeping, dizziness (accompanied by heat intolerance at times), physical awareness of the device; [Psychosocial], fear, including fear of death and preparation for death, changes in mental functioning, changes in lifestyle including clothing not fitting, loss of control, driving an automobile, and spousal overprotectiveness. The primary psychosocial concerns of the S.O.s were fears, including fear of death and preparation for death, family and role changes, being overprotective and driving an automobile. Mental changes and heat intolerance have not been addressed in the literature previously.

Assessment and prevention of osteoporosis through use of a client self-reporting tool

Osteoporosis is an age-related process that affects one out of every four women above 65 years of age. This article focuses on the assessment of osteoporosis through use of an osteoporosis assessment tool that is filled out by the client. The tool requests information about the woman's demographic profile, chief complaint, related symptoms, pain profile, risk profile, past medical history, nutritional history, fitness profile, menopausal history and self-care practices. The tool also includes information for the health care provider to complete about the client's lab analysis. Assessment needs to be extensive in order to uncover the specific factors that place an individual at risk for the silent changes of osteoporosis. The health care provider can elicit the aid of the client in securing such a comprehensive assessment.

Synthesis and antihypertensive activity of 5-amino-2-pyridinecarboxylic acid derivatives

The synthesis of various substituted 5-amino-2-pyridinecarboxylic acids and their derivatives is described by three general methods: (1) reductive alkylation of methyl 5-amino-2-pyridinecarboxylates (2) and subsequent hydrolysis; (2) alkylation of the urethane (9), followed by hydrolysis; and (3) selective NaBH4 reduction of the appropriate amide of (2), followed by hydrolysis. A more specific process was used for the 5-(phenylamino) compound, i.e., nucleophilic displacement of nitrite from methyl 5-nitro-2-pyridinecarboxylate by sodioformanilide and subsequent hydrolysis. Many of these 2-pyridinecarboxylic acid derivatives were potent antihypertensive agents in the spontaneously hypertensive rat (SHR). Optimization of structural parameters for this activity yielded compounds 54, 55, 34, 65, and 22, which were selected for further study in the renal hypertensive dog (RHD). Based on these studies, one compound, 5-[(4-fluorobenzyl)amino]-2-pyridinecarboxylic acid (65), was selected for preclinical toxicity evaluation. Based on the toxicological findings, it was decided not to pursue compound 65 clinically.

Synthesis and antihypertensive activity of 5-thio-2-pyridinecarboxylic acid derivatives

Synthesis of various substituted 5-thio-2-pyridinecarboxylic acids and their derivatives is described by three methods, i.e., displacement of nitrite from methyl 5-nitro-2-pyridinecarboxylate (10) by a thiol anion, alkylation of methyl 5-thio-2-pyridinecarboxylate derived from reaction of the diazotized methyl-5-amino-2-pyridinecarboxylate (5) with thiocyanate followed by borohydride reduction of the product, and alkylation of 5-thio-2-pyridinecarbonitrile followed by hydrolysis. 5-Thio-2-pyridinecarbonitrile was obtained from butyl 6-methyl-3-pyridyl sulfoxide (2) by nitrosation and dehydration of the oxime. Many of these 5-thio-2-pyridinecarboxylic acid derivatives were orally active antihypertensive agents in the spontaneously hypertensive rat. Optimization of the structural parameters for this activity yiedled 5-[m-trifluorobenzyl) thio]-2-pyridinecarboxylic acid (41) and its sulfoxide, 42. Further biological studies with these compounds are described.

The absolute configuration of SU 23397: a novel neuroleptic agent

The absolute configuration of a novel chiral neuroleptic agent SU 23397 (I) was determined by ORD comparison of (+)-5-methoxy dihydro coumarilic acid (VIII), a synthetic precursor of SU 23397 (I), with (+)-dihydro coumarilic acid, whose absolute configuration is known. This assignment was confirmed by oxidative degradation of (+)-5-methoxy dihydro coumarilic acid VIII to D-(+)-malic acid.

The absolute configuration of the enantiomers of glutethimide and aminoglutethimide

Aminoglutethimide (Elipten¿ CIBA) was resolved into the optical antipodes I and II. The endocrinological properties and the absolute configuration of both enantiomers I and II were determined. Most of the steroidal synthesis inhibition was found in the (+) enantiomer II. On the basis of circular dichroism, the R-configuration was assigned to the (+) enantiomer II.